DE916299C - System for the transmission of signals, in particular a telephone switching system - Google Patents

Description

The invention relates to a telecommunications system for the transmission of signals, in particular in telephone exchanges.

The commonly used telephone systems require subscriber lines to be switched through For different connection sets a considerable amount of electromechanical Counters and controls. Furthermore, in general, a relatively large number of Intermediate members in an office required to allow each a connection from a desired one Input can be established to a desired output. Same are for the selection the necessary lines and for the control and signaling devices necessary for establishing the connection quite complicated.

In particular, telephone switches are considered for consideration in accordance with the invention used with electromechanical switches. For the further development of such telephone systems so-called semi-electronic switching devices have recently become known, which use electronic means for the control of the connection setup and for the connection the connection electromechanical switches. There are also other versions has been proposed which, in addition to the control for establishing the connection, also for the

use electronic means to switch the voice connection itself. Such designs are referred to as fully electronic systems.

On the basis of the fully electronic systems, according to the invention, an embodiment in the Proposed form that the lines or channels to be connected to one another in the switching device are scanned at different times and that the transmitted via a channel pulse-wise sampled signal energy with the help of an electronic device of a temporal Subject to shift, which is the time difference between the sampling times for corresponds to the incoming channel and the desired outgoing channel.

This scanning is expediently carried out by a distributor, which is in an uninterrupted manner Cycle samples all channels at a sampling frequency that is higher than the highest signal frequency to be transmitted. This distributor is equipped with electronic switching means assigned, which when initiating a transmission via one of the channels via the distributor in the corresponding sampling time come into effect and the establishment and maintenance cause a connection during the uninterrupted continuation of the cyclic scanning. It is therefore every channel as a result of the cyclical scanning in the exchange by a A series of pulses of a specific pulse frequency are shown, which are characteristic of each channel Time slot (equals the distance from a fixed time stamp, e.g. synchronization pulse) occur and are modulated with the signals or the language. Each channel is within one Sampling cycle assigned a certain time slot, and the electronic device causes controlled from the usual number dialing pulses, a relative time shift in the signal transmission from the incoming to the outgoing channel, the time difference between the two channels in the sampling cycle is equivalent to.

This switching system described above also allows all necessary for the connection establishment Functions such as locking the occupied circuits against other occupancy as well to determine the delay times that are necessary for the election processes. the According to the further invention, means for carrying out these switching operations consist in the use several connection sets switched in parallel, each consisting of a line pair (call seeker), a line selector with telephone number memory and a special signal transmission circuit exist.

A cathode ray tube is expediently used as a distributor; Medium cyclically deflected electron beam elec-. troden scans to which the individual channels are connected, and causes the triggering of pulses of a certain time slot, if at a These electrodes have a certain potential which characterizes a call state. These impulses which also corresponds to the signals transmitted over the channel concerned, e.g. B. Dialing pulses or speech, are modulated, are on the one hand as carriers of these signals via the switching device, on the other hand used for the control of the switching equipment itself. For this purpose, one of the connecting clauses common control device separating the modulation components from the basic pulses made and the former transmitted via a special signal transmission circuit.

To achieve the necessary time shift, either variable delay elements (delay elements) can be used, or the signal energy is stored and controlled by a time counter at the correct point in time retransmit.

An embodiment of the invention and some modifications thereof are shown below Description explained in more detail with reference to the drawings. In these shows

Fig. Ι a schematic representation of the circuit structure;

Fig. 2 and 3 show a distribution tube used for the connection of subscribers in such systems with the associated subscriber connection circuit, 'Fig. 4 is a common device, Fig. 5 is a device for forming the pulses carrying the messages,
6 shows the line search device, FIG. 7 shows the telephone number storage device, FIG. 8 shows the line selection device, FIG. 9 shows a system which shows how FIGS. Fig. 5 to 8 show, taken together, a connection set, of which several are available, as Fig. Ι shows;

Fig. 10 shows a set of curves leading to Explain the work processes of a part of the system,

11 shows a partial representation of a delay line, which can be used in the device of Fig. 8,

Fig. 12 shows a modification of the circuits of the common control device of a line finder circuit according to FIGS. 4 and 6.

13 shows a further modification of the line finder circuit, which can be set for Figure 6;

Fig. 14 is a modification of the pulse generator according to FIG. 5;

Fig. 15 and ιό show different shapes the phone number memory and the line selector circuits, which, taken together, replace the two circuit arrangements of Figs can;

Fig. 17 is a diagram showing how Figs. 4, 13, 14, 15 and 16 are laid together have to be in order to have a complete transmission and switching system again form;

FIGS. 18 to 20 show a further exemplary embodiment which, in particular, enables two-way communication enables and consequently a somewhat differently designed signal transmission circuit has, but otherwise largely coincides with the other exemplary embodiments.

As stated above, the system shown in the application example is essentially built up three parts, as Fig. ι shows: i. all

ίο subscriber lines, for example twenty, whom the numbers ι to 20 are assigned and of which each line in a subscriber station, such as indicated at 21, ends; 2. the control device common to all of these line circuits, which is designated by 22, and 3. a group of connection sets, one of which required for each simultaneous call. Each of the connection sets in turn consists of one Line finder circuit 23, a device for

ao design of the dialing pulses 24, a dialing register circuit 25 and a line selector circuit 26. These various main components are interconnected by conductors 27 to 38, as shown in FIG. 1. For the purpose of simplifying the description, in the following first only considered a one-way traffic connection.

As shown, all of the lines 1 through 20 terminate in the shared controller 22.

This device 22 performs a scanning process, which is preferably by means of a suitable Tube is carried out, which has an electron beam, which in turn over each Line slides.

If one of these lines carries a potential which corresponds to a call state, transmits the common facility 22 signals over conductors 27 and 28 to all parallel connection sets, So also the line finder circuit 23 of the first connection set, which is in the The following description is used for explanation. This line finder 23 responds, to find the calling line and the signals via wire 33 to the pulse generation circuit 24 to pass on.

When the election begins, this circuit, labeled 24, generates election pulses that are in the election register circuit 25 can be counted and stored. The dial pulse register 25 is then used to control the line selection circuit 26, which contain a delay line without any other suitable time shifter can.

The incoming voice signals are then transmitted by the communal facility 22 via the Wire 28, line finder circuit 23, wire 33, line selector circuit 26 and further via wire 36 back to the communal facility 22 from which they were created on the Transfer the selected outgoing line. The part of Fig. 1, which the line finder 23, the pulse generation circuit 24, which contains election register 25 and line voter circuit 26, is referred to as a connection set. For 'specific purposes the system can receive a sync frequency from the communal facility 22 over line 29 are routed to the line selector circuit 26 or to the line finder circuit 23. the five conductors 27, 28, 29, 36 and 37, which lead to and from the communal facility «2, can also be switched multiple times with other connection sets of the system, as shown below will.

The distributing action of the communal facility 22 can be provided by a rotating distributor in the form of a cathode ray tube, as shown in more detail in Figs. 2 and 3, can be achieved. The manifold contains a cathode 40, the usual grid 41, the focusing and anode electrodes 42, horizontal baffles 43 and vertical baffles 44. Here distribution currents different phases from a corresponding scan control via conductors 45, 46 and 48 are placed on the horizontal and vertical baffles, respectively, such that a cyclic rotation of the electron beam is effected. At the end of the tube 39 are twenty impact electrodes 49 to 68 provided with the individual lines 1 to 20 are connected. These impact electrodes can represent secondary electron-emitting elements, which are assigned to a common anode 69, which has the function of a common Provides output for all dynodes formed from the impact electrode and anode. Of furthermore, if necessary, a screen or screen 70 can be provided which or which has openings that allow the electron beam to impact a dynode only when the beam is in alignment with her. This means that a possible secondary emission is ioo other electrodes. The exit of the manifold 39 is via the conductor 71 from the Anode 69 connected to a device for separating the signal currents from the basic pulses, which is described below, and connected via these to the conductors 27 and 28, which lead to the line finder circuit lead, as Fig. 1 shows. The output from line selector circuit 26 can, as shown, be placed via the line 36 to the grid 41 of the distributor and serves to the Modulate beam in accordance with the selected signal energy. Referring to Fig. Ι can therefore the energy in the conductor 71 after an adapted delay, which in the line selection equipment 26, as will be described further below, is generated, are brought to the grid 41 via conductors 36, to the intended desired traffic channel between a given pair of lines.

The common control device 22 is shown in FIG. 4. To get a better picture of the To be able to make relationships, it is assumed that a fundamental frequency of 10,000 Hz is used as the scanning speed of the rotating distributor was chosen. This frequency is high enough to Tone frequencies with one for the call transfer

sufficient fidelity. For the twenty line system contemplated, the fundamental frequency is derived from a 200 kHz oscillator 72, which is preferably crystal controlled. This higher frequency is expediently chosen because it is easier to build a stable oscillator with higher frequencies than one for ro 000 Hz. In addition, in some modifications of the invention shown later, the 200 kHz oscillation can also be used for other control purposes. The sinusoidal frequency generated in the main oscillator 72 is lowered by the frequency divider 73 to the frequency of 10 kHz.

The output frequency of the frequency divider 73 is applied via a go ° phase shifter 74 to the vertical and horizontal sets of baffles 43 and 44 of the manifold 39, as shown schematically. This arrangement serves to rotate the electron beam having a frequency of 10,000 rotations per second, so that each of the dynodes 49 is scanned to 68, which are shown in Figs. 2 and 3, once in every ¹ Ao 000 seconds. Incoming lines i, 5 and 20 shown are connected to dynodes 49, 53 and 68, respectively.

With a typical subscriber station circuit is referred to, as it is used in the system according to the invention. Such a subscriber station is connected to each of the incoming lines 1 to 20. Only the intercom connected to line 5 is shown here. The microphone 75 is in series with the number switch 76 and the normally open hooked contact JJ. The telephone 78 is consistently across the line since the pager at the subscriber station is not specifically shown for the sake of simplicity. Accordingly, the signal for calling the called party may consist of a special tone which, reproduced on telephone 78, attracts the subscriber's attention.

As is common practice, the hook contact JJ is open in the idle state. However, it is closed at the beginning of a call and thus completes the circuit of the calling line via a low-pass filter 79 and the subscriber station assigned to the line. In this case, a negative potential is applied from the battery 80 to the assigned dynode 53. Normally the dynode electrodes 49 to 68 are at the same potential as the anode 69 and no current flows. The aforementioned negative potential causes a potential difference and thus causes a secondary emission current to flow in the tube 39 in response to the impact of the electron beam and thus a negative output pulse in the outgoing line 71. The pulses are preferably signal-modulated to a depth of only 25 to 50%, so that there is always a sufficient amplitude to supply the energy required to establish the connection and maintain it independently of the modulation signals. The negati \ ^r s import!

Pulses caused by the actuation of the selected dynode 53 go to the grid of the inverted tube 81. The anode circuit of the tube 81 is coupled to the grid of the tube 82. This is used to limit these pulses to a certain level, so only the modulated part which flows through incoming impulses. In this way the output energy of this tube is which which represents speech signals, practically up to 100% modulated. These limited pulses are then passed to the cathode amplifier tube 83 and thence forwarded the cathode amplifier output conductor 28 to all connection sets. A second output energy is tapped at the terminals of the cathode resistor of the reversing tube 81. These pulses are fed to a limiter tube 84 which serves to limit the pulses to a to limit constant level in such a way that the modulation components are removed from them. Of the The anode circuit of the tube 84 is coupled to the grid of the cathode amplifier tube 85. These serves to transmit the pulses 86 via the common supply resistor 87 and the conductor 27 to the grid of a line finder holding tube 88 (in Fig. 6) of the line finder 23 (in Figs. 1 and 6) in the first connection set, which is to be considered here, and parallel to it to the grids of the to conduct the corresponding line finder interrupters of all other connection sets. After the Pulse 86 has gone through resistor 87, let it be designated with 89, so that the pulse that actually reaches the grid of tube 88 and that of the other similar tubes, the pulse 89 is. If one assumes first that none of the grid of the interrupter conducts current, then this is Impulse 89 is almost as strong as impulse 86. But under other conditions it can, as in the following should be explained, be significantly weaker than impulse 86. In the absence of any Signals at the cathode of this interrupter 88 are capable of the above-mentioned pulse 89 at its grid not to generate a current flow at the anode, since the bias voltage applied to the grid is sufficient is far negative.

In the line finder 23 (Fig. 1 and 6), an oscillator 90 is provided, which normally operates at a frequency that is slightly lower than the output frequency of the frequency divider 4. This oscillator can operate, for example, at a frequency which is around one thousandth of a second is lower than the frequency of the frequency divider. The output energy of the oscillator 90 becomes a limiter amplifier 91 is supplied, which serves to generate rectangular dial pulses 90 °. These pulses are in a network consisting of the capacitor 92 and the resistor 93 is differentiated to produce the waveform 94 which is sent to the control grid of the limiter tube 95 is laid. The output pulses 96 of the tube 95, which are the leading edge of the pulse 90 ° and correspond to the positive part of the pulse pattern 94, are placed on the cathode amplifier tube. The resulting impulses 98 are

led to the cathode of tube 88 and aim to make the cathode of this tube negative so that the tube is closer to its ignition point. The tube 88 thus remains inoperative, except the case when the pulses 98 applied to the cathode of tube 88 coincide in time with the aforementioned incoming pulses 89, which via the conductor 27 their grid be forwarded. Sufficient bias is applied to the grid of tube 88 from battery 99 placed so that it takes the combined amplitudes of pulses 89 and 98 to this tube actuate. As the oscillator 90 continues to move in relation to the output energy of the frequency divider

^{1 to} shift 73, the pulses 98 begin to coincide with the pulses 89, which come from the calling line, and thus change the bias voltage of the tube 88 and generate an output pulse 100 in the line 32. These output pulses 100 are then applied to an amplifier and phase corrector circuit 102 via the capacitor 101 so that its output is synchronous with the frequency of the frequency divider 73 and the pulses 98 from now on regularly match the incoming pulses 89 from the predetermined calling line. As soon as the oscillator falls in step, the pulses of the line 32 are applied via the rectifier 103 to the integration network 104 to a control grid of a level control tube 105 operating with a delay. The actuation of the tube 105 increases the positive voltage on the screen grid of the limiter tube 95 and thus also the amplitude of the output pulses 96 and the pulses 98 dependent thereon. The value of the resistor 87 (FIG. 4) and the grid current characteristic of the tube 88 are such that the total positive bias of its grid with respect to its cathode does not exceed a predetermined small amplitude, regardless of the magnitudes of the pulses 98 and 86 which are given to the cathode and the grid of the tube 88 via the resistor 87, respectively. Thus, the square wave pulses 98 of the tube 97 increase in amplitude as the bias voltage of the tube 95 changes. Since, in this way, therefore, the sum of the pulses 89 and 98 is approximately constant while the value of the component 98 increases, it is clear that the size of the pulse 89 must decrease accordingly.

This decrease in the amplitudes of the pulses 89 causes other line finder switching tubes that of tube 88 are the same and are in different sets of connections are prevented from responding as will be explained later with reference to FIG.

This decrease in pulse 89 therefore decreases the responsiveness of tube 88 in the did not consider first connection set because the total input voltage between grid and Cathode is not diminished. Therefore, the pulses 100 are approximately constant in amplitude. These Pulses 100 from line finder switch tube 88 are also transmitted over line 32 and the Coupling circuit 106 is applied to a control tube 107, which is used to reverse the bias of the input switch tube 108 of the signal transmission circuit. The tube 108 is normally prepared by the barrier bias so that the pulses sent to them from the output of the cathode amplifier 83 are given via the line 28, do not go through the tube. After operating the tube 107 when a predetermined incoming line is selected as described above, but has the blocking grid of the Tube 108 has such a potential that the tube during the moments which the time channel a correspond to such predetermined line, becomes conductive. Then the combined Dialing and speaking pulses 109 from the output of the tube 108 via line 33 to the pulse generator 24 (Fig. 1 and 8) and placed on the line selection device 26 (Fig. 1 and 8). The energy applied to the line selection device (Fig. 8) is not allowed through until the Line selection is carried out, as will be described later.

Now that the line finder 23 has worked, the pulses 109 from the line 33, which correspond to the time slot assigned to the line accepted as the calling line is transmitted to an integration network 110, which is preceded by a pulse stretching circuit which corresponds to a peak voltmeter. These impulses are then in the tube 111 is amplified and via the transformer 112 to the control grid of the limiter amplifier tube 113 and to the control grid of a second Tube 114 out. The integration network 110 in the input circuit of the tube 111 operates as Low-pass filter and lets the dialing pulses through, while the higher-frequency speech signals do not go through can. The limiter 113 is used to shape the incoming dialing pulses and to cut so that they get a square pulse shape 115, which in turn differentiates in the network 116 and go to the control grid of the dial pulse switch tube 117. The tube 117 is like this biased that they take the negative part of the differentiated impulses that form the front flanks of the quadrangular Dialing pulses 115 correspond, suppressed and only the positive part of the differentiated pulse which corresponds to the edge terminating the pulse 115. Usually the tube is 117 by the voltage drop across its screen grid resistor 118, which together with an anode of a normally conductive tube a Multivibrator circuit, which operates in conjunction with the tube 114, is close the point lying at the cut-off point for the anode current. The time constants of this iao Circuit are set so that the leading edge of the first dial pulse is used to the To actuate tube 114 and to close tube 119 lock. The low pass filter 120 in the grid circuit of the tube 119 causes this condition to be maintained stays until the last pulse goes through

is whereupon the multivibrator circuit returns to the normal position and the dial pulse switch tube 117 is made insensitive. Thanks to these special blocking circuits, temporary Actions before and after the election do not have any influence on the memory. The output pulses from the dial pulse switching tube 117 are via the line 35 to the dial pulse register (Call number memory) 26 of FIG. 1, these pulses through the resistor structure 121 and 122 (in Fig. 7) go to the grids of the first register level.

The dial pulse register circuit consists of a series of tubes, of which tubes 123, 124, 125 and 126 are shown individually and connected as conventional trigger circuits for the operation of a binary (dual number) counter. The squares 127, 128 and 129 represent other similar register toggle circuits. A sufficient number of these register circuits must be provided in order to be able to count any dialing number in the office. In a system for twenty lines, the five shown are sufficient. At rest, the tubes shown on the right, for example 124 and 126, are conductive and serve to bias tubes 123 and 125 to the blocking point. Furthermore, the voltages occurring in the register circuits are transmitted in a manner to be described in more detail later via the lines 130 to 139 to the line selection arrangement (Fig. 8) and serve there to bias the various delay interrupters to the reverse voltage and the tubes with the delay zero to make conductive. The one about the. Incoming pulses from conductor 35 reach the first register circuit, which contains tubes 123 and 124. If the register circuit is in the normal position, that is, when the tube 124 is conductive and the tube 123 is biased to reverse voltage, then a voltage is present on the line 130, which receives the associated zero device of FIG. 8 actuated, and on the line 131 a voltage which blocks the delay switch tube in a manner to be described in more detail later. The first incoming pulse from the line 35 goes through resistor 121 to the grid of the tube 124 and beiwirkt an interruption of the anode current flow, this tube, but at the same time ^1, the tube becomes conductive 123 and control voltages are applied to the lines 130 and 131 which to serve to lock the first tube with zero delay and to open the first delay switch tube. The output energy of the tubes 124 is transmitted via a line 140 to the second register circuit, which the tubes 125 and. 126 and serves to alternately move the conductive state from the tube 126 to the tube 125 and from 125 to the tube 126. This process ¹ occurs alternately every time the breakdown circuit 123, 124 returns to the normal position, for example every time the tube 124 becomes conductive. It is therefore clear that the second register changes its switching state with every second pulse applied to the first register, while the first register changes its switching state with every incoming pulse. The third register 127 is controlled in the same way via the line 141, so that it changes its switching state every time the second register circuit finds its way back to the normal position, ie every time the tube 126 becomes conductive. The register 127 changes its switching state once during two actuations of the second register circuit. The fourth register 128 is caused to be its. To change the state every time the third register 127 finds its way back to the normal position, and: the fifth register 129 is controlled in the same way by the output of the fourth register 128.

In the following now with reference to FIG. ¹ 8 the control of the delay brought about by the actuation of these various registers will be explained in more detail. For a better understanding of the processes in this system, it should be assumed that the number switches 76 (FIG. 4) are numbered from ι to 20 for each line and thus represent the twenty lines. Each number switch on an individual line is set so that when a desired line is selected, a number of pulses are transmitted to the exchange which corresponds to the difference between the numbers of the calling and the called line. Because: it is obviously necessary to achieve temporal shifts in the transmission of the message energy, which correspond to the time difference between the scanning of two lines in the cathode ray probe circuit. The various signal pulses cause, with the aid of the above-described register circuit of FIG. 7, the selection of the necessary time shift which produces the correspondence with the line to be called. For this purpose, each register circuit is provided with a zero switch 142, 143, 144, 145 and 146, which are assigned to the first, second, third, fourth and fifth register circuit. In the same way, different delay selection elements (delay gates) 148, (of 5 μ & duration in a system comprising twenty * lines), 149 (10 ^ s), 150 (20 ^ s), 151 (40, «s ) and 152 (80 ^ s). Each of these delay elements has a delay line. Delay switching tubes 153 and 154 are arranged at the output of each of these delay lines and are shown individually using the example of elements 148 and 149. It can be seen that the same delay lines and switching tubes are provided for the other delay selection circuits. Under normal conditions, ie before any pulse arrives, the system is biased so that the zero switches 142 to 146 are all actuated, so that none of the pulses 109 which arrive via line 33 from the line finder circuit of FIG Delay suffers. That is why these im-

pulse 109 directly from line 33 through zero switch circuits 142 to 146 in series and from. as transferred via line 135 to the output switch tube 136. If it is assumed for the moment that the tube 136 is not blocked, then its anode would transmit corresponding pulses 157 via the line 36 to the control electrode 3.9 (FIG. 4) and from there back to the calling line. When the first register operates for the first time, the control voltage is applied from the line 130 to the line 131, thereby rendering the tube 153 conductive, the tube 142 being biased to the blocking point. Therefore, if only one pulse is selected, a delay of 5 ^ s is created so that the energy arriving on line 33 flows through a first delay switch 148 and the remaining zero switches 143-146. The second pulse moves the control voltage from the line 131 back to 130 and causes the zero switch 142 to be rendered conductive again. the tube 153. is blocked in the delay switch 148. At the same time, the second register operates and shifts the potential from the line 132 to the line 133, the second zero switch 143 being blocked and the switching tube 154 in the second delay switch 149 being opened, which results in a delay of 10 ₁ MS between the lines 33 and 135 is introduced.

In this way, the second pulse generates a zero delay in 142, a delay of 10 ^ s in 149 and zero delays in 144 to 146. The third incoming pulse does not touch the second register circuit, but in turn actuates the first register circuit and thus leads both the s- ^ s delay switch 148 as well as the io-jUS switch to cause a 15 second delay in the incoming energy; will. The fourth pulse then returns both registers, ie the first and the second register, to their normal position, actuates the third register 127 and thus generates a delay of 20 με at the delay switch 150. The fifth pulse in turn leads the 5- ^ s delay switch 148, so that there is a delay of 25 ^ a. The next pulse switches the line of the 5- ^ s delay off and the line of 10 / ^ s on, giving a total delay of 30 με . The next pulse turns the s- ^ s delay line back on, while it makes the 10- and 20- ^ s delays ineffective. This results in a delay of 35 με. The next following pulse makes the delay lines 148, 149 and 150 ineffective, but brings the fourth delay switch 151 with its 40 με delay into the circuit. The other pulses then bring the delay switches 148, 149 and 150 with 5, 10 and 20 ^ s into the circuit in the same order and introduce a further 5 με delay in succession until the delay switch 152 is actuated, whereupon the process is in steps repeated by 5 ms. With the five delay switches it is therefore possible to establish any delay condition for the twenty lines. It will be understood that if a different number of lines are used, additional stages must be provided for the dual count register, as well as additional zero switches and delay switches similar to those described above to provide an appropriate delay for interconnecting any of a number of lines to ensure.

After the desired number has been dialed, the signal energy is used by the calling party Line, as described, via the circuit of the common control device and line 33 in the connection set to the grid of the Transfer tube 156. The output pulse 157 tube 156 is then routed via line 36 to the control electrode of tube 39 as shown. The speech modulation of the pulses 157, which arrive via the line 36, is then generated each time Changes in the electron flow of the tube 39 when the beam is in alignment with the electrode of the called line is standing. This change in energy becomes the corresponding one via the line Low-pass filter 79 of the called party and routed to the receiver circuit 78. For call purposes A tone frequency can be transmitted to any suitable facility at the called To operate the subscriber station, or the output of the receiver 78 can be designed in such a way that that attention can be drawn directly by a whistle or other transmitted sound.

In the foregoing, for the purpose of simplifying the explanation, it has been assumed that the tube 156 is conductive. In fact, however, this tube is normally biased on locks so that the Dialing pulses that arrive via the line circuit 23, no others during the dialing Affect lines. This reverse bias of the output switch tube 156 is generated by the breakover circuit, which contains tubes 158 and 159 is controlled. Tube 158 is normally conductive and holds the grid of tube 156 biased to the locking point. These tubes 158 and 159 are in turn controlled by the tube 119 as follows: As explained above, the tube 119 5 blocked at the beginning of a series of pulses. At this point it sends an ineffective positive pulse through capacitor 160 to the grid of tube 158. Once the dialing operation completes, tube 119 returns to its conductive state and transmits a negative impulse. This negative pulse interrupts the current in tube 158, which in turn causes the tube 159 and also the switching tube 156 to become conductive. To this Way can the message energy from the line ιαο 36 can be transferred to the line of the called subscriber.

To avoid the called line before it is seized by another line finder to protect another connection set as soon as the listener of the called subscriber part of the

Fork is lifted, a portion of the delayed pulse 157 from the line 36 is over the line 37, the blocking resistor 161 (in Fig. 4) is passed to a busy pulse generator, from where it is sent to the Grid of a busy switching tube 163 is placed. This limits the possible maximum value of the after the positive line search pulse applied to the tube 85 when the receiver is picked up at the called station 89 to a value which is not sufficient, the line finder switching tube of a searching To operate the line finder.

When the call has ended and the calling party hangs up, the register of FIG. 7 and the circuit for the output switch must be 158, 159 of FIG. 5 are returned to the normal position. This is done using the Tubes 164, 165 and 166 of FIG. 7 carried out. If the line finder circuit 23 blocks, the tube 105 of FIG. 6 is on the blocking point brought and via line 31 thus the potential lowered on the grid of the tube 164. This creates the multivibrator circuit that runs the tubes 164 and 165 contained, made to work and thus made the tube 165 conductive. To this a5 way a negative pulse is sent through line 167 and capacitor 168 to tube 166, which is biased to the locking point, so that this impulse has no effect. If now the line finder becomes free by hanging up the handset at the calling subscriber, the Tube 105 of FIG. 6 becomes conductive again and increases the bias of tube 164 via line 131, whereby the multivibrator circuit 164, 165 causes will return to normal. The return to the normal situation of this circuit causes a positive pulse to be transmitted to tube 166, which reduces the voltage at the common Resistor 169 low, removing all of the register circuits and the control tubes 158, 159 are enabled for the output switch. To avoid excessive mutual interference between the various register circuits and to avoid the tubes of the control circuit for the output switch, the resistor must 169 be sufficiently low-resistance. In order to ensure the restoration of the rest position, the Tube 164 carry sufficiently strong currents. This tube circuit therefore expediently consists of several parallel tubes.

In order to explain the processes in the system, a call from line 1 for the Line 5 can be traced through the entire circuit arrangement. If the calling party the line 1 lifts its receiver from the cradle of its microphone station, becomes a negative potential applied to the dynode electrode 49. When the beam from tube 39 contacts contact 49, cause the secondary emission of this contact creates a pulse in the common anode 69. This pulse then flows through the reverse circuit 81, the limiting amplifier 84, the cathode amplifier 85, resistor 87 and route 27 to line finder switching tube 88. This generates then an Imupls 100, which serves to switch the oscillator 90 to the calling line. The pulses 96 which are derived from this oscillator (and therefore also those from these newly formed pulses 98) are kept in time coincidence with the input pulses 89. Thanks to this correspondence, only that set of pulses 89 which corresponds to the time channel corresponding to the calling line now considered is passed as pulses 100 through tube 88. All other pulses 89, which correspond to the time channels of other calling or called lines, are suppressed. Therefore, only the impulse of the line under consideration is chosen. These selected pulses 100 are then used to actuate the control tube 107, which is the downstream Input switch tube 108 makes conductive at the right moment. The output pulses 100 of these tubes 108 thus only represent the desired ones of all pulses received by the anode 69.

The calling subscriber then dials the number 5, which in this case is four consecutive Lowering the bias on the dynode 49 results. It follows that the single set of pulses which, due to the scanning of this dynode via line 71 arrives, suffers four consecutive decreases in amplitude. These impulses are about line 71, anode circuit of inverter tube 81, limiter tube 82, cathode amplifier 83 and line 28 on the control grid of the input switch tube 108. As a result of the effect the limiter tube 82 the four appear Reductions in amplitude of the pulse set as four complete interruptions in this series of impulses. These incoming impulses with their four dialing interruptions are then through the tube 108 is passed on to the line 33 as a pulse. The pulses 109 are transmitted over the integration network 110 where the dialing breaks be transformed into voting signals. These selection signals go through the amplifier in, the transformer 112 and the limiter 113, where they get a square waveform 115. These square-wave pulses pass through a differentiation network ii6, the selector switch tube 117 and the line 35 to the register circuit. At the same time, the voting signals go through the other Integrating circuit 120 to the delayed acting control circuit, which consists of the tubes 114 and 119 consists of switching from the normal position to the anomalous one (i.e. 114 actuated and 119 deleted). This device causes an increase in the positive screen grid bias of the selector switch tube 117, so that they iao easily passes through. Successive pulses 115 then control the first three registers, see above that the third of these is placed in the abnormal state, but the first two in the normal state to be led back. This puts the delay switch 150 into the circuit.

switched and generates a delay amounting to 20 μβ, which is the time difference in the course of a cycle of the electron beam in the manifold 39 between the scanning of the contact 49 and the output contact connected to the line 5 53 is equivalent. At the same time, the increase in the anode potential of the tube 119 a positive pulse through capacitor 160 placed on the tilt assembly 158 and 159. However, this has no effect, since it already has the tube 158 encountered in a conductive state. This causes the output switch tube 156 during the entire Blocked voting time. Once the choice is finished, the positive potential from the grid of the tube 114 removed, whereby the from the tubes 114, 119 existing delay device is returned to the rest position in which the tube 119 conductive and thus the screen grid bias of the tube 117 is reduced and prevents further Signals reach the register in FIG. At the same time it causes the anode potential to decrease at the tube 119 the transmission of a negative pulse through the capacitor 160 to the Tilt assembly 158, 159, tilting them to their abnormal condition, the tube 159 becoming conductive. This process unlocks the output switch 156. The speech signal pulses 109, which via the Line 33 arrive, are placed on this output switch tube 156. This tube then gives output impulses 157, which are led via the line 36 to the control grid 35 of the tube 39, and cause the beam to coincide with those arriving via line 1 Signals every time it is in contact with the electrode 53, which corresponds to the line 5, is amplitude modulated. These pulses change their amplitude in accordance with the sound signals and are then via the corresponding low-pass filter 79 on the receiver 78 of the called Transfer subscriber station.

When the calling party ends their call and hangs up, the calling party becomes Loop circuit is open and the negative potential is removed from electrode 49. If the If the beam then passes over the electrode 49, no output pulse is triggered and via the line 71 transmitted, and the connections to the line finder circuit are interrupted. Simultaneously the output power of the level control tube 105 is interrupted, and thus also stops the control of the oscillator 90 so that the line finder is free and thus any can record a new incoming call. At the same time, the potential of the tube 105 is raised the line 31 is applied, and the tubes 164, 165 are triggered. These tubes 164 and 165 return to their normal switching state, where 164 is conductive. This causes a positive pulse which is passed through capacitor 168 to tube 166 got. This in turn puts a trigger potential on the common resistance 169, whereby all register circuits are returned to the rest position, so that only those without delay working circuits 142 to 159 are actuated again. In the same way, the tilting arrangement 158, 159 released, tube 158 remaining conductive. In this way, the entire connection set returned to the rest position.

In order to weaken the amplitude of the impulses of any incoming line effectively, that other line seekers are prevented from subsequently seizing the same calling line 1, the delayed control tube 105 and the associated circuit are provided. the end From the above description it can be seen that when two or more subscribers are at the same time the office use a number of pulses with different times in the line circuits the communal facility (Fig. 4) are available. This from the output of the cathode amplifier 83 outgoing pulses are all applied in parallel to all connection sets. But when a connection set has been assigned, it is necessary that the pulses from this assigned connection set remain without effect on the occupancy of another connection. A better understanding the processes in the system which prevent the aforementioned double occupancy are shown in FIG. 4 and 6 and the curves of FIG.

The pulses from the anode 69 of the tube 39 are applied to the grid of the tube 81, which has separate anode and cathode outputs. The pulses occurring at the anode output of the tube 81 and changing in amplitude in accordance with the incoming signal are shown in curve ΐο ^Λ . These pulses are limited in the limiter 82 to the level 170, so that only the modulated or the changing amplitude portions 171 of these pulses are passed through the anode circuit of this tube to the cathode amplifier 83. The energy is preferably only modulated to 25%, so that the change in modulation represents the smaller part of the pulse energy. These pulses are used for call transmission and are of no interest in connection with the feature which will now be considered.

The pulses from the cathode output of tube 81 are those of primary interest. These impulses are limited in the tube 84 and passed through the cathode amplifier 85, so that a Series of pulses 86 of the same amplitude is generated, as shown by curve 108. These impulses 86 are sent through the resistor 87 as pulses 89 to the grids of all line finder switching tubes 88 (Fig. 6) given. The blocking oscillator 90 generates an oscillation 172 (curve 100), the period of which is a little longer than the time interval between two pulses 89. The oscillation 172 is on the clipping levels 173 and 174 clipped, then differentiated and again limited to impulses generate, the leading edges of which substantially increase with the increase in vibration 172 between the Limit levels match.

These pulses are preferably substantially longer than the incoming ones. Impulse 89 and go

through the cathode amplifier 97. The pulses 98 resulting therefrom are applied to the switching tube 88. Since the frequencies are slightly different, the phase or timing of the pulse 89 is constantly shifted with respect to the pulse 98 until the pulse 89 with the pulse 98 as it is. curve 100 shows coincides. When: this happens, line finder switch 88 (FIG. 6) is actuated so that the pulses pass through amplifier 102 to and from oscillator 90. now in step with the. Hold impulses. The phase correction of the peak voltage amplifier 102 is set so that the sine wave 172 passes through zero just before the arrival time of the pulse 89. The pulse 98 is then generated in a fixed temporal relationship to the pulse 89 *, as is shown by the first waveform of the curve io ^E. Once these pulses are synchronized, the delayed level control tube 105 is disabled, causing the screen grid bias from tube 95 to rise so that the selection pulses 98 rise from their normal search amplitude to a significantly higher hold amplitude, as does the second waveform of curve io ^E shows. This reduces the real height of the pulse 89. Therefore, the pulse 89 which reaches the grids of the line searcher switching tubes, which correspond to the tube 88 ;, is very small in all the other line searchers, as is shown by the third waveform of the curve io ^£ . If so, then a match between these pulses 89 and the normal or dial pulse 98 in such other line finders, prolapse, goes as the fourth waveform of FIG. Io ^£ shows no signal by the switching tube of such other line viewfinder.

When the called subscriber answers, this is done by closing his or her line circuit 5, the same potential as that of the calling line is applied to the dynode 53 If If special precautions are not taken, this potential would damage another line seeker cause the called line to be seized and thus an additional connection data set to prove. To prevent this, there is a busy signal device 162 and a busy switch 163, which work as follows:

Upon completion of the output switch selection, the tube 156 begins the speech pulses 157 via line 36 to control grid 35 of the Transfer tube 39 as described. Part of the energy of these impulses 157 is from; branches off the line 36 of FIG. 8 and goes via the line 37 and the isolating resistor 161 to the busy signal image 162, which strengthens, limits and strengthens these impulses again, sharp and constant. Forms amplitude pulses. For this purpose is the limiting level of the speech restriction tube 6 * 2 soi that the speech modulation of the speech impulses 171 never under a predetermined little. Minimum value reduced. The newly formed: impulses from 162 are given to the grid of the busy switching tube 162 in order to make it highly conductive at the moment do. This switch tube 163 then presses a fixed upper limit on the amplitude of the positive Pulse 89 so that it does not reach an amplitude which is sufficient for a called line to be occupied by another line searcher. Preferably, however, this upper limit is high enough for a guide who is already on the called line switched to hold on this; this for the purpose that the process of Selection of a line that has already been seized as the line to be called, this previous connection shouldn't interrupt.

In Fig. 11 is a delay line for a system in which greater delays are required is shown. For the shorter intervals, which in the delay switches 148, 149 and 150 to 5, 10 and 20 ^ s may be needed artificial delay lines of known form are easily needed. For longer delays however, acoustic delay means are preferable. The line can, for example, from consist of a container 175 filled with mercury

176 is filled and, a length of 1 - y. having. In the equation, V means the speed of the sound in the liquid and D the desired delay time. At the input end, a crystal, for example a quartz crystal 177, is provided in an adapted mounting ring 178 which has an electrode 179 which is coupled to the line 180 for the input signal.

On the exit side is a second crystal 18 mounted in a mating ring 182 having an electrode 183 and to the output lead 184 is coupled. In order to take into account the expansion of the liquid, a. Essay 185, which sits on the container 175, is provided will. As explained above, amplifiers are provided in each delay switch, see above that the total loss is equal to that of the associated zero switch.

In the above description, the circuit arrangement is a complete switching facility according to the invention. the The invention is of course not limited to this special circuit arrangement, but rather the circuits used can be modified in many ways without doing so there is a deviation from the principle on which the invention is based. Some of those modified Circuit arrangements are in, the further. Figures shown and intended in the following Description will be explained in more detail.

Fig. 12 shows, for example, a modified arrangement of the line finder and the common Control device. In this arrangement they are the same; HaiUptoszillaitor 72, the frequency divider 73, which uses phase shifter 74 to control the beam in tube 39. Against it is the control circuit in which the separation

of the signal and synchronizing pulses takes place, compared to the circuit shown in Fig. 4 easily modified. When the negative output pulse from distributor 39 via line 71 to the inverter 186 and then, into which two cathode amplifiers 187, 188 goes, the tube 188 carries the speech signal to line 28 which extends over all connection sets. This signal was in his Modulation depth not increased because this function ίο is assigned to the connection set in this example is. The control signal, on the other hand, is on again limited a constant amplitude. This happens in a slightly different way with one Latch circuit, which contains a double diode 189, which the amplitude of the signal limited to the grid of the cathode amplifier 187. This cathode amplifier feeds through a Series resistor 87 the grids of all connection set tubes 88, as above, in the first embodiment

ao example was explained.

These tubes are normally biased sufficiently above the cut-off point that the signals 89 alone at the input electrode do not cause a change in the output and, as previously described, the collapse of the signals 98 derived from the local oscillator is necessary in order to achieve to cause a response at all. In place of the use of a local oscillator, which is tuned to a little more than 10 kHz, a local oscillator 190 is provided in this system, which works at 200 kHz + ο - ο, ι ° / ο ·. The output pulses 89 of the tube 187 are applied to the grid of the signal switching tube 88, while the output energy of the oscillator 195 is brought to the multivibrators 191 and 192 by two frequency dividers in order to generate the desired pulses 96, which are transmitted via the tubes 95 and 97 cause a selection signal 98 to be transmitted to the cathode of the same tube 88. The time relationship between: the impulses 89 and 98 is, as already described, so long. shifted until the dialing pulse 98 at the cathode of the tube 88 is applied simultaneously with a control pulse 89 on its grid. Thus, tube 88 provides a pulse 100 to the grid of tube 193 of the delay breakover circuit which includes tubes 193 and 194 and thus does so. The breakover circuit switches to its anomalous position in which the tube 194 is conductive, whereby the pulse generating circuit 195 is provided with a sudden increase in voltage. This delay breakover circuit has an operating period which is set by the constants of the tube 193 grid circuit. If it immediately returns to the normal position, the voltage at the pulse shaper 195 suddenly drops again, so that this change in voltage practically equates to a long positive pulse which is fed to the pulse shaper. The pulse shaper is used to differentiate this pulse and to suppress the front edge. The trailing edge has the desired delay. This rear part is then amplified and applied to the oscillator 190 in order to synchronize it with the main oscillator 72. Keeping the relative displacement between these two oscillators constant holds the pulse displacement of pulse 98 with respect to pulse 89 and serves ¹ to connect the line finder firmly to the selected line, as described above. After stepping, the pulses 100 of the tube 88 are rectified in the rectifier 103, and serve to block the tube 105, whereby the gain of the tube 95 is increased and consequently also the amplitude of the pulses 96 and 98, which are transmitted to the cathode of the tube 88 be placed. As a result of the fact that a higher frequency is used for the local oscillator, more stable operation and more precise switch-on are obtained.

The busy switching tubes 196 and 197 work like beforehand in order to impose an upper limit on the pulses 89, which is somewhat lower than that Limit which is imposed by the limiter 189. This new limit is high enough to keep a line finder occupied first, but also low enough, the occupancy of another: Line seeker to prevent. In performing these operations, tubes 196 and 197 in the same way as the duo diode limiter 189. At the moment of the arrival of a positive pulse from the busy pulse shaper 162 on the grid of the tube 196 this is completely unblocked and therefore works as a diode to reduce the potential on line 27 to prevent it from growing above the potential of its cathode. The tube

197 works as a reverse lock to unload the negative potential that remains at the end of such pulses.

Another line finder circuit which can replace that of FIG. 6 is shown in FIG. 13 shown in the same grouping as shown in FIG. The line finder oscillator arrangement is substantially the same as that of FIG. However, the comparison oscillator 198 leads here at the same time a frequency division by and is moreover from the main oscillator 72 instead of just the selected one Line impulse controlled. The comparative oscillator

198 operates at a frequency that is slightly below 200 kHz. Its 50 kHz output is via the limiting differentiating circuit 199 connected to the multivibrator 200 synchronized to 10 kHz. The output energy of this multivibrator 200 is applied through the differentiation network 92 and 93 to the tube 95, which is to serves to shape and strengthen the impulses. The tube 95 is normally above the lockout point negatively biased, but the leading edge of every square wave provided by multivibrator 200 is strong enough to temporarily iao the grid positive over part of that square wave do. A negative pulse 96 of approximately 5 / s duration is thus in the anode circuit generated. A cathode amplifier tube 97 leads the control pulse 96 as a pulse 98 to the cathode the line finder tube 88. If the signal 89 at the grid of the tube 88 with the above-described

benen dialing pulse 98 coincides in time, the tube is conductive and gives a pulse 100 on three points, namely to the diodes 103 and 201 and via the wire 32 to the voting circuit, if it is of the type shown in FIG.

This pulse 100 is rectified in the tube 201 and fed to the integration network 202. The negative potential of the integrator is amplified in the tube 203 and lowers the potential in the cathode resistor 204, which is common belongs to tubes 203 and 205. The degradation of this potential does the Tube 205 conductive. Therefore this tube starts to pass a sine wave from the main oscillator 72, which is constantly placed on the line 29 to its grid. This amplified wave is then over a phase correction circuit 206 which is used to connect the oscillator 198 with the main oscillator 72 interconnect. Accordingly, the progress of the election is now stopped so that the pulses 89 through the tube 88 in each case at the right moment to the open line finder switch tube 108 flow and thus this causes the desired signal pulses from line 28 to Line 33 to be transmitted in the manner previously described in connection with FIGS.

Simultaneously, the application of the pulses 100 to the diode 103 actuates the tubes 105 and 95. Thus the occupancy of other line finders, as already described, is prevented.

In the system just described contain the dial register circuit and the line selector device 7 and 8 a binary counting arrangement and delay lines to the to accomplish the desired time shift of the incoming pulse signals. A something modified arrangement of a pulse register circuit and an associated line selection circuit is shown in Figs. These can be used together in place of FIGS. In Fig. 14 is also a modified one Pulse shape circuit shown, which can replace the circuit 5. When these circuits 14, 15 and 16 in place of FIGS. 5, 7 and 8 are used and when the line finder of FIG. 13 and the shared controller 4, as was last assumed, are used for this purpose, the result is a complete one System with an arrangement of the individual circuit diagrams according to FIG. 17.

Returning to Figure 14, the incoming Pulses 109 with their dial breaks through the tube in, the transformer 112, tube 113 and tube 114 in one above already described manner led to an output line 35.

The selector switch tube 206, which corresponds approximately to the tube 117 of FIG. 5, is normally through the voltage at their barrier from the control circuit (toggle arrangement) 158, 159, where 158 normally conductive, biased to conductive state. As described above, locks tube 119 at the beginning of a series of dialing pulses, with an ineffective positive pulse emitting, and at the end of the same responds again, giving a negative impulse through the diode 207 leads to the control circuit 158, 159. This negative pulse from tube 119 blocks tube 158 and causes tube 159 to conduct to become. This biases the tube 206 to the locking point and locks the selector switch, so that temporary and speech modulations or even additional dialing the register can not influence. At the same time, a control voltage is sent out via conductor 38, which unlocks the output switch 156 control grid.

Moving on to Figs. 15 and 16, it should be noted that that the output line 35 with a number of tripping circuits 208, 209, 210 and 211, each containing a pair of tubes, is connected. As many of these circuits are provided as there are subscriber lines. Normally the right tube of each pair, with the exception of input pair 208, is biased to locks and in turn tensions the associated switching tubes 212, 213 and 214 on their locking grids to the blocking point. If a series of dialing impulses has been received, please note: that one of the right tubes remains conductive and thus its interrupter is allowed, that Let signal through.

The work process in the register can be described as follows: The first trip circuit 208 has no associated switch tubes, and tube 215 is normal conductive. A first pulse via conductor 35 from the pulse generating circuit (Fig. 14 or Fig. 6) blocks the tube 215 of the trip circuit 208 and makes the tube 216 conductive. If this is conductive is, a negative pulse from their anode circuit to the grid of the normally conductive tubes 217 of the trip circuit 209, which blocks this tube and the tube 218 to become conductive. This operation on tube 218 serves to become the first interrupter 212 open. The negative second pulse of the pulse forming circuit disables tube 218 and shifts the conduction state to tube 217. A no negative pulse from the anode of tube 217 disconnects the tube 219 and returns the first switch 1 to the locked state, whereby the Conductivity is shifted to the tube 220 in the next register 210. The blocking of the tube puts the first switch tube 212 in the blocked position while the tube is in the conduction state the second interrupter 210 unlocked. This sequence of operations is shown in the following Registers repeatedly until the last dialing pulse has been sent.

Therefore, at the end of the election, only the switch that matches the number of received dialing pulses. If again it is assumed that the line 1 the Line 5 calls, the fourth circle is not blocked.

If it is assumed that line 3 is calling line 5, the second circuit is not blocked. As a result, any further impulses that arrive at the grids of the interrupters for example via lines 221, 222, etc., only through switch 213 to the common Output line 223 performed, as described in more detail in connection with FIG shall be.

After the calling party has hung up the phone, the trigger circuit becomes Release of registers 208 to 211 in the same way as in connection with FIG. 7 has been described, operated. This circuit is controlled so that the tube 165 is normally open the lock point is. If the line finder 23 finds a line and connects to it, a signal is given over the line 31 so that the tube 165 becomes conductive. The resulting negative pulse from tube 165 is fed to tube 166 via capacitor 168, but is ineffective because this tube 166 is already blocked. However, if the line finder trips, the tube 165 is returned to its normal locked condition and thereby suffers a positive pulse on tube 166. This is a negative pulse in the anode circuit of the Tube 166 amplifies and serves to control all register trip circuits 208 to 211 and the control circuit 158, 159 to be returned to the normal position. The way the speech signals are sent to the selected called line, e.g. line 5, will now be considered in detail in conjunction with FIGS. 15 and 16. In This application example is used instead of the timely generation of transmission delays for the speech signals of the calling line, these are saved and released again later. ITm to determine the right moment for the release of these stored signals, the line selector counts the pulses transmitted between the caller's channels and the called subscriber's lying time channels.

For the purpose of the counting to begin at the moment on the time slot of the calling line corresponds to, a synchronization pulse is sent from the line finder tube via line 32 fed through the pulse shape amplifier 224 to the sync counter 225. Then bring the Pulses 226, which, controlled by the oscillator 72, in a further pulse shape amplifier 227 are generated, the processes in the system continue in the same way as for the register circuits 208 to 211 described earlier, with the help of counters 228, 22g and 230. Es only three counters are shown here, corresponding to the three switches 212, 213 and 214 described. These counters and their associated interrupters work together to determine the moment of the Release of speech energy to the called. Control line. In the consecutive Actuation of the counter they put potentials on the 'wires 221, 222 etc. But if only the switch 213 is open, only the potential on wire 222 is applied to the common line 223 and so on the time of the release of the speech signals to the called line precisely defined, how short is explained.

The incoming energy from the line finder switching tube 108 is by means of the line 33 to a low-pass filter, combined with a speech amplifier 231, which serve as storage means for the incoming speech signals. This on Speech signals occurring at the output of the filter 231 are continuously sent to the control grid of the Tube 232 is laid, which corresponds essentially to tube 156 of FIG. Of course none can Energy is transferred until the election is complete and the reverse bias is removed from the control grid Tube 232 removed by control member 158,159 is, and also until the time in which the actual control pulses from conductor 223 to the control tube 233 are placed for the locking switch, which in turn, the bias on the locking grid this tube 232 removed. The latter bias is removed in the proper timing which depends on which of the interrupters 212 to 214 is open at this time. The tube 232 becomes therefore open at the moment determined by the incoming line signal, so that the energy from the storage filter 231 is only transferred to the output line at the right time the conductor 36 is transmitted.

The pulse shape amplifier 224 is connected to the line 32 to generate the pulses 100, which correspond to the time channel of the calling line, to be received directly from the line finder circuit. Therefore, in this arrangement the count is proportional to the difference between calling and called line, and each number switch must be set up to send such a differential number.

In many cases, however, it may appear necessary to start counting from a fixed zero point that can be derived from the synchronization distributor itself. Therefore can for this purpose, the pulse shape amplifier switched off from the line 36 and instead with the Frequency divider 73 be connected. Then synchronization begins instead of a line finder pulse assume which different time slots for each different calling line possesses, from a zero point, which always corresponds to the time channel of the line 20 at the distributor. the Count is then in agreement regardless of the calling party's timing with the number of the called line. In such a case, the line is preferred omitted. This simplifies the setup of the subscriber station, since the number switch is on can be equal to all of them, as is common practice. Since it is not necessary either, the time difference To measure between the calling and called subscriber station can last with this described system multiple rotations

the dial can be used in a simple manner for signaling, with only the Pulse shaping circuit (of Fig. S or 14) a corresponding Changes must be made by adding more register switches and counters in addition can be provided in order to be able to record and evaluate several series of dialing pulses.

In the foregoing description was initially an application example of the invention, which 4, 5, 6, 7 and 8 after the grouping of Fig. ι contained, explained. It was then assumed that Fig. 12 replaces Figs. Finally it was assumed that Figs Place of Fig. 12 and Fig. 14 in place of Fig. 5 and that Figs. 15 and 16 in place of Figs. 7 and 8 are introduced. The most recently accepted compilation therefore corresponds the grouping as shown in FIG. It can be seen that the circuit diagrams of FIGS 14 can be interchanged in any of the combinations and that likewise the 6 and 13 are interchangeable with one another. The composition of FIGS. 7 and 8 is also shown with the combination of FIGS. 15 and 16 interchangeable.

With regard to FIG. 12, it should be noted that this figure is not only compatible with the combination of FIG and 6 or with the combination of FIGS. 4 and 13, but the upper part of the FIG. 12, which represents the common control device, can be compared to FIG. 4 and the lower part FIG. 12, which shows a line detector circuit, can be exchanged separately with FIG will. In the case of such individual interchangeable chucks comprising parts of FIG. 12, the Operations performed by tube 108 in the line finder from those described a little different. This is because the common facility of Fig. 4 has a limitation which consequently is not embodied as being carried out by the tube 108 of FIGS has been described, while in the case of Fig. 12, the collaborative facility carries out these operations and the tube 108 of this figure is the delimitation of the signal. Therefore, if for the moment FIG. 6 with the upper part of the Fig. 12 is combined, it must be assumed that the tube 108 of Fig. 6 is operating as a limiter. However, this does not require any changes in the circuits, only those of the constants, which can be carried out without difficulty for all cases where it is necessary.

In the embodiment of the invention described above, it has been assumed that the called Participant picks up his hook switch in the usual way to answer. this is not necessary with a suitable arrangement of the facility of the subscriber station, so that the Use of the tube 166 and 196 in FIGS. 4 and 12, respectively, to protect the line finder, thus it does not occupy the called line, is not necessary and the tubes are removed from their sockets can.

With tubes 166 and 196 removed, it is It is also possible to create a two-way voice circuit as follows: The call is in the for 9 or 17, and the called subscriber station is called, wherein following the call, the number of the line of the calling subscriber is signaled. The called Participant operates his hook switch and dials the number of the calling party Participant. This call is made over a new call set in exactly the same way like the previous call, so that in every direction there is a path between the calling and the called Participant is established. So that there is no whistling in the apparatus, the entire gain is Each link circuit is set to be less than 1.

A two-way call can also be set up with the help of a single connection set, when the line selector circuit of Figs. 15 and 16 is employed and when the circuits in the line search circuits of Figs. 6, 12 and 13 and in the line selector circuit of Fig. 15 and 16 can be expanded slightly. The necessary Measures are explained in the following section.

Line 32 is connected through a capacitor and resistor to the grid of control tube ² 33 (Fig. 16) for the output switch. In the same way, the line 37 is closed by a capacitor and a resistor to the grid of the control tube 107 of FIGS. 6, 12 and 13 for the input switch. Of course, the additional resistors and capacitors, together with the resistors and capacitors 106 shown, must be dimensioned in such a way that the signals do not affect the lines 32 and 37. As a result of this change, the speech signals can go through in either direction after the call is through. The input switching tube 108 now receives signals at its grid at a point in time which corresponds to the time channel of both, ie the calling and called subscriber. These then go via the low-pass filter and the amplifier 231 to the grid of the output switch 232. This switch in turn carries signals of a time slot which corresponds to the time of the channels of both the calling and called line, to the grid of the manifold 39 and to the subscriber concerned, such as has been described above. The gain control is set so that the system gain is less than 1 to prevent whistling.

For the purpose of simplifying the illustration, the counters 225, 228 to 230 are triodes shown provided. In this case, however, it is advantageous to use tetrodes or pentodes for them with a pre-tensioned grid and barrier grille in an adapted manner to the running speed of the To improve counting. Furthermore, known factors can increase the speed can be used in this or that circuit. If so desired, the

demands on the speed accuracy are reduced by the fact that the number of Lines in the distributor 39 is lowered. It can also be seen that the various batteries and sources of negative potential shown taken from one or a few power supplies can be. Furthermore, the various potentials shown are created by a the same symbol are displayed, not necessarily the same as each other. You can also use the various flip-flops shown, such as. B. the number memory or the counting chain of the Line selector, double triodes are used instead of the two triodes, as they are for example are already shown in FIG.

Furthermore, instead of the audio frequency filter, which was used as a memory for the signal energy in the example described last, other suitable memory means can of course also be used. Although the simple low-frequency filters appear to be the most suitable form of energy storage, capacitor storage can also be used together with switching means to divert the capacitor charges, if this appears necessary. In such a case, the capacitor storage means only have to be dimensioned sufficiently large that no full charge can occur due to the incoming signal pulses, and they have to be controlled in such a way that they release their charge to them at the moment of scanning the desired line. It has already been pointed out in the exemplary embodiment just described that, by making certain circuit changes, perfect two-way communication can be achieved without disturbing other channels or through other channels. In the following, a further embodiment will now be briefly described with reference to FIGS. 18 to 20, which shows this two-way communication * o possibility through a special design of the signal transmission circuit. In this case, FIG. 18 shows the circuit arrangements for the distributor and the common control device, which correspond to FIG. 4, as well as for the dial pulse generator, the latter deviating slightly from the arrangements previously shown for this (cf. FIG. 15), but in principle works equally. 19 shows the line finder, which roughly corresponds to the arrangement according to FIG. 13, and the novel signal or speech circuit for intercom operation. Finally, FIG. 20 shows the selection register and the counter of the line selector which, apart from minor deviations to be described, corresponds to the arrangements shown in FIGS. 15 and 16. The mode of operation of the arrangement is initially the same as already described with regard to the scanning of the subscriber lines of the common control device, the setting and blocking of the line finder. At the moment when the calling line is scanned, pulses are generated in the distributor tube, which are fed to the common control device via conductor 37 and are freed of the modulation components in the latter. The unmodulated basic pulses are fed via wire 48 to switching tube 49 of the line finder, and the modulated components of these pulses are fed via wire 42 to input switching tube 77 of the speech transmission circuit. The setting of the line finder to the calling line by means of the pull-in generator and its synchronization to the sampling frequency takes place in the same way as described in connection with FIG causes the control voltage for the delayed operating level control tube 73, corresponding to tube 105 in FIG. 13, after the integration element 67, corresponding to 201 in FIG. 13, is taken off. This saves the second diode 103.

The speech input switch tube 77 is normally adjusted by the bias on the second control grid so that the pulses applied from the output of the cathode amplifier 41 via line 42 cannot pass. However, after the response of the tube 76 to the pulse 63 in the selection of a predetermined incoming line, as described above, the potential of the second control grid of the tube 77 makes that tube conductive during the moments corresponding to a particular time slot. Therefore, dialing and speech pulses are transmitted from the output of the tube 77 via the line 8r (FIGS. 20 and 18) to the dialing pulse generator (FIG. 18).

In this circuit, the incoming, corresponding to those sent by the participant Impulse signals modulated pulses into the pulse shape required for the memory setting reshaped, with other, higher-frequency modulation components, so z. B. Speech modulation, in this Order remain ineffective. The mode of operation of this arrangement has already been described in detail above explained.

Apart from the use of double triodes in the individual links of the telephone number memory its structure and mode of operation corresponds completely to the arrangement shown in FIG. At the end of the dialing process, only the switch corresponding to the number selected is again Store open. Assuming line 3 is calling line 5, the second will be Switch 101 will be unlocked. Pulses that reach the grid of the interrupters, e.g. B. about the Conductors 109, 110, etc., can only be accessed through the switch 101 to the common output conductor 111 reach.

The counter corresponds to that shown in FIG Arrangement. In order to start counting at the instant which is the sampling time corresponds to the calling line, a synchronization pulse is sent from the line finder switch tube 49 via conductor 74 and the remote pulse amplifier to meter ο. Nor- iss sometimes the left meter tubes are 115, 117

etc. all live. The synchronization pulse 123 causes the conductivity to change from tube 115 to tube 116.

The counting chain is switched on by the main oscillator 23 via the conductor 124 at a distance of 5 .ms supplied negative pulses in the manner already described above for the arrangement of FIG. When going through the chain one after the other potential is applied to the control grid of the interrupters 100, 10.1, 102 etc., however In this case, only the tube 101, which is suitably pretensioned from the number memory, can be effective and thus the correct timing of the release of the signal energy stored in the signal transmission circuit determine.

As already mentioned, this was transmitted to the input of a switching tube Jj at the respective sampling times of the calling line. In the output of this tube, which is controlled by the line finder ao so that it is unlocked in the same time slots, a device 127 consisting of a low-pass filter and an audio frequency amplifier is arranged, which serves as an energy store. From the output of this device, the energy is continuously applied to the control grid of an output switching tube 80, which, however, can only transfer this energy when its blocking state is released. This takes place at the point in time determined by the line selector and corresponding to the sampling instant of the called line, in that a pulse is sent via the tube 101 to the control tube 79 for the output switch, which temporarily opens the switch 80. The low-pass filter 127 simultaneously converts the signals fed to the input switching tube yj into the original speech signals. These are passed through the output switch 80 and a level control element 129, as already described, to the grid of the distributor tube and modulate the electron beam at the moment of scanning the called line. The call is expediently carried out by means of a tone frequency.

When the called subscriber answers, take his voice streams or other signals accurately the same path as that of the calling party. To achieve this, the input interrupter and the output switch tube of the signal transmission circuit not only from the Line finder or from the line selector, special from both one after the other in the corresponding Times controlled. For this purpose, on the one hand, is the one coming from the line selector Conductors not only to the grille of the control tube 79, but also to the grille of the control tube 76 for the input switch, and on the other hand, the line finder switch via the conductor 74 is also connected to the grids of both control tubes. There is a feedback path in this circuit is present between the two line connections, the entire gain must must always be kept below 1 throughout the entire system. The level controller is for this purpose 129 provided.

To protect the called line from being seized by a connection set, if the receiver of the called station is lifted for the purpose of answering a call, the Pulse from the time channel switch tube 100, 101 or 102, which is currently actuated, via the conductor 111 and a pulse shape amplifier 131 is placed on the grid of the occupied interrupter 132. This causes a negative pulse in the conductor 48, which neutralizes the line pulse 50, which otherwise at Initiation of a call in this conductor is generated. Because of this, no further caller switch can be used corresponding to the tube 49 are operated. When the calling party is his handset after the end of the call, the various circuits are delayed working control tube 73 (Fig. 19) controlled, returned to the rest position. The register and the Selector switches, which are held during the connection, are activated by deleting the Tubes 133, 134, 135 in the already described Way de-energized.

From the foregoing description of the invention is to identify which resources were provided for maintaining a connection between a called and the calling station to ensure and prevent the same time to _go, that one of the participants involved in causing a further line viewfinder to select his line, ie to intrude. In addition, it goes without saying that the change in response sensitivity which takes place in response to the synchronization of the line finder oscillator can also be used for blocking purposes other than those indicated. Likewise, the busy signaling (negative pulse in conductor 48) can also be applied to circuits other than those shown.

The possibilities for the realization of purely electronic circuits for according to the invention Switching systems operating are ensured by the circuit arrangements shown and described By no means exhausted, rather arise for the expert with knowledge of the specific Principle of the solution many other ways to carry out the necessary switching operations. The arrangements described are therefore only to be assessed as exemplary embodiments on which the invention does not apply is limited.

Claims (60)

Patent claims: i. Message transmission system, in particular telephone switching system, with use exclusively electronic switching means for the optional connection of two of a large number of channels, characterized in that that the channels to be connected to each other (z. B. 27 and 36 in Fig. i) in the Switching equipment to be scanned at different times and that the over one channel transmitted and transmitted in pulses sensed signal energy with the help of an electronic device (26 in Fig. 1) a temporal Shift is subjected, which is the time difference between the sampling times for the incoming channel and the desired outgoing channel. 2. Transmission system according to claim 1, characterized through a distributor (22 in Fig. 1) for uninterrupted, cyclical scanning of the individual channels as well as by electronic switching means, which upon initiation a transmission via one of the channels via the distributor (23 in Fig. 1) to Approaching coming and establishing and maintaining a connection during cause the uninterrupted continuation of the cyclical scanning. 3. Transmission system according to claim 1 and 2, characterized in that as a result of cyclic scanning of each channel in the exchange by a series of pulses specific pulse frequency is shown, which is characteristic for each channel Occurrence time slot and are modulated with the signals or speech. 4. Transmission system according to claim 1 to 3, characterized in that the effectiveness of the electronic switching means from the uninterrupted cyclic scanning (22 in Fig. 1) is dependent. 5. Transmission system according to claim 1 to 4, characterized in that as a distributor (22 in Fig. 1) a cathode ray tube is used and that the electronic switching means a number of connection sets connected in parallel (27 to 29 and 36, 37 in Fig. 1) form that respond when on a channel connected to the distributor there is a call state and the channel is being scanned. 6. Transmission system according to claim 1 to 5, characterized in that each of the Channels within a sampling cycle is assigned a specific time slot and that the electronic device a relative time shift of the incoming via a channel Energy in relation to another selected channel causes the time difference of the two channels in the sampling cycle. 7. Transmission system according to claim 1 to 6, characterized in that the electronic Facility includes a line voting circuit (26 in Fig. 1) that is in agreement with signals transmitted over the calling line a certain selects another channel. 8. Transmission system according to claim 1 to 7, characterized in that by the Line selector group selected the sampling time assigned to the desired line in which the arrived via the calling line and delayed accordingly Signal energy via a coupling device that then becomes effective and the same or another distributor is passed on to the desired line. 9. Transmission system according to claim 1 to 8, characterized in that the scanning speed of the distributor is higher than the highest signal frequency to be transmitted. 10. Transmission system according to claim 1 to 9, characterized in that the connection sets have a plurality of line finder circuits (23 in Fig. 1), which one on a specific, identifying for a call Voltage at one of the line connections taking effect and occupying a certain line finder control device is assigned jointly, which when they respond by transferring a control potential to one of the line seekers occupies this and locks it against other occupancy. 11. Transmission system according to claim 1 to 10, characterized in that each line finder with a memory for recording the number of the called. Line is connected and that the same connection set Associated line selectors both with the line finder and with the phone number memory is coupled and. in dependence of. the attitude of the latter is controlled so that it is responsible for the retransmission of the calling line incoming signal energy on the line to be called required time shift generated. 12. Transmission system according to claim 8 and 11, characterized in that the line selector after its setting is connected to the sampling distributor via the coupling device. 13. Transmission system according to claim 5 and 12, characterized in that the line selector circuits are connected to the control grid of the cathode ray tube serving as a distributor and the electron beam modulate with the messages to be transmitted. 14. Transmission system according to claim 1 to 13, characterized in that switching means are assigned to the connection set which prevent any other occupation of the lines (channels) connected to one another via it. 15. Transmission system according to claim 14, characterized in that any other occupation of the calling line immediately after the occupancy of a connection set is prevented by this line, while the Called line is blocked against other seizure when answering the call will. 16. Transmission system according to claim 10, characterized by locking switch means, which prevent the line finder occupied by a calling line from being accessed by others to address the calling lines generated by the cyclic scanning pulses. 17. Transmission system according to claim 1 and 11, characterized in that the switching means for generating the time shift the transmission energy from a plurality of pulse delay elements of different Runtime exist, of which depending on the recorded in memory Dialing pulses are switched on certain elements in the transmission circuit. 18. Transmission system according to claim 17, characterized in that the delay elements at the sampling times of the lines in binary relationship and that to set the required time shift the suitable term elements can be selected individually or in combination. 19. Telephone switching system according to claim ι to 5 with a number of subscriber stations of the usual structure, which have a subscriber line are connected to the exchange, characterized in that the subscriber lines in the exchange with Impact electrodes of a cathode ray tube are connected, whose electron beam passes through deflection voltages supplied by a relaxation generator is controlled so that the impact electrodes cyclically scans and triggers a pulse from these electrodes, if they have a potential corresponding to the call status on the connected line and that an electronic switching device (common control device) responds, which the incoming energy to a line finder device transmits. 20. Telephone switching system according to claim 19, characterized in that the individual impact electrodes together with a common anode secondary emission dynodes form. 21. Line finder arrangement for transmission systems according to claim 1 to 20, characterized by means of selection, which normally the individual channels of different time slot continuously check, also by switching means, which at the time coincidence checking a channel with signal pulses supplied by this channel is effective and thereby halt the progressive testing process, thereby removing this channel is selected and permanently switched off, as well as by switching means, which after Selection reduce the effective amplitude of the signal pulses so far that they further Cannot influence the line finder. 22. Line finder arrangement according to claim 21, characterized in that a local oscillator is used for the test, which supplies pulses with a frequency that is only slightly different from the sampling frequency, preferably a slightly lower frequency, and that the selection of the calling line and its continuous connection is thereby warranted that when signal pulses from this line coincide in time with pulses supplied by the oscillator, the latter is drawn in synchronism with the sampling frequency. 23. Line finder arrangement according to claim 21 and 22, characterized in that at the same time with the selection of the calling line by the line finder of a connection set an increase in the sensitivity of the switching devices of this connection set for over The selected line receives incoming signals. 24. Line finder arrangement according to claim 21 to 23, characterized in that the of The basic impulses (unlocking impulses) supplied to the local generator and those from the signal pulses supplied to the calling line are mixed in a device which so is designed that they only synchronize these pulses when they coincide in time of the generator passes on with the pulse frequency of the signal pulses and ςο at the same time causes an increase in the amplitude of the basic pulses, which increases the sensitivity of the connection set is brought about. 25. Line finder arrangement according to claim 21 to 24, characterized in that for Preventing other line seekers from responding to the calling line negative impulse is transmitted to the mixing devices of the remaining connection sets, which block these mixing devices in the sampling times of the calling line. 26. Line finder arrangement according to claim 21 to 25, characterized in that according to successful selection of the desired channel from the connection set occupied by the calling channel further blocking impulses in the time slot corresponding to the desired channel and pulse frequency are fed to the other connection sets, which these connection records to an occupancy of the desired channel for the duration of the connection prevent. 27. Line finder arrangement according to claim 21 to 26, characterized in that an electron tube circuit is used as the mixing device serves, to which the signal and the basic pulses are fed as control pulses and which is so biased that only when the two pulses coincide in time the Tube becomes conductive and transmits the impulses. 28. Transmission system according to claim 1 to 10, characterized in that the temporal Shifting the incoming signal energy is caused by the fact that the signal energy is stored and that the signal save in the times assigned to the desired channel to pass on the stored energy is released. 29. Transmission system according to claim 28, characterized in that the storage the signal energy takes place in the line finder. 30. Transmission system according to claim 28 and 29, characterized in that as Line selector is a time counting device that counts the time interval between the sampling times for the calling and the desired channel counts and triggering switching means controls which the signal memory at the sampling times assigned to the desired channel trigger and thus transfer the stored signal energy to the next channel. 31. Line selector according to claim 30, characterized in that it is the setting of the memory for the call numbers of the desired channel counts down step by step, where the step speed depends on the scanning speed for the channels. 32. Line selector according to claim 30 and 31, characterized in that its _Fortschalt takes place at time intervals that correspond to the difference between the sampling times of two adjacent ones Channels on the distributor. 33. Line selector according to claim 30 to 32, characterized in that when it is set to the member of the telephone number memory identified by the recorded dialing pulses Switching means become effective, which the incoming channel and the desired outgoing channel with the storage device for the signals in the link given times. 34. Line selector according to claim 30 to 33, characterized in that it consists of an electronic There is a counter and that each individual position of this counter is assigned an electronic switch, the is controlled by the counter and via which the stored signal energy on the further channel is transmitted. 35. line selector according to claim 34, characterized in that for each existing Channel a certain position of the line selector and such an electronic one Switch is provided and that only the line selector after its setting The switch assigned to this setting is opened, thus reducing the stored signal energy only to be transmitted to the desired channel at the sampling times assigned to it allowed. 36. line selector according to claim 34 and 35, characterized in that the electronic Switch when counting the pulses recorded by the phone number memory one after the other be opened and closed again, with only the switch remaining open to the desired channel. 37. Transmission system according to claim 1 to 20, characterized in that the of triggered by the distributor when swiping a channel in the call state and in their amplitude in accordance with those transmitted over this channel Signals modulated pulses in the common control device from their modulation component are separated and that the lower, unmodulated part of the pulses for Control of the electronics used to establish and maintain a connection Switching means is used. 38. Transmission system according to claim 37, characterized in that the unmodulated Parts of the pulses have constant amplitude. 39. Transmission system according to claim 37, characterized in that the upper, modulated Part of the impulses that transmit signals to the output circuit. 40. Transmission system according to claim 37 to 39, characterized in that the device consists of a tube circuit with two outputs to split the pulses, the one peak limiter for obtaining the basic impulses of constant amplitude> and one Contains suppressors for the elimination of the modulation component of the pulses. · 41. Transmission system according to claim 37 to 40, characterized in that the pulses less than 70%, but preferably less than 50 ° / »are modulated. 42. Transmission system according to claim 37 to 41, characterized in that the separation The impulses are carried out in a tube, the grid of which is supplied with the modulated impulses are., whose anode circuit is connected to the © itter of the suppressor tube and this Controls the tube in such a way that only the modulation signals appear in its output circuit, at the largest signal level practically up to 100%> are modulated, and their voltages occurring at the cathode resistance are fed to a limiter tube and control them so that in their output modulation-free pulses of constant amplitude occur. 43. Transmission system according to claim 37, characterized in that the modulated Part of the impulses are passed through a special signal transmission circuit, its Input and output at different sampling times of the channels to be connected is opened at the appropriate times. 44. Transmission system according to claim 43, characterized in that the opening of the Input circuit from the line finder, the iao of the output circuit is controlled by the line selector (counter). 45. Transmission system according to claim 1, 17, 18 and 43, characterized in that at Use of term elements to determine the necessary time Shift the modulated pulse parts are guided over these delay elements. 46. Transmission system according to claim 1, 28, 29 and 43, characterized in that at Use of stores for the signal energy, these stores in the signal transmission circuit are arranged. 47. Transmission system according to claim 43 and 46, characterized in that as Storage means a low-pass filter and an audio frequency amplifier are used. 48. Transmission system according to claim 43, characterized in that the input of the Signal transmission circuit via the common control circuit with the anode of the manifold is coupled, while the output is directly connected to the grid of the manifold connected is. 49. Transmission system according to claim ι to 3, 37 and 43 to 48 for two-way communication, characterized in that inputs and outputs of the signal transmission circuit both in the calling channel and in the dem times assigned to the called channel are opened. 50. Transmission system according to claim 43, characterized in that each connection set such a signal transmission circuit is permanently assigned. 51. Transmission system according to Claim 43 to 50, characterized in that the opening the input and output of the signal transmission circuit through electronic switches is effected. 52. Transmission system according to claim 43 to 51, characterized in that each Signal transmission circuit having an input switch tube and an output switch tube and that the anode circuit of the input switch tube is connected to the grid circuit via the signal memory the output switch tube is connected. 53. Transmission system according to claim 52, characterized in that as switching tubes Pentodes are used. . 54. Transmission system according to claim 52, characterized in that each interrupter a control tube is assigned, of which the control tube assigned to the input tube by unlocking pulses delivered by the line finder at the sampling times for the calling channel is controlled, while the control tube for the output tube from the counter of the line finder in the Called line, associated sampling times, pulses to unlock the output tube be forwarded. 55. Transmission system according to claim 54, characterized in that the grids of the two control tubes are interconnected are such that they alternate between the line finder and the line selector accordingly the sampling times for the calling and the called channel can be controlled. 56. Transmission system according to claim 43, characterized in that level control means in the output of the signal transmission circuit are arranged, which always keep the overall gain less than 1. 57. Transmission system according to claim 11 or 30, characterized in that as switching elements for the call number memory or the counting devices tube flip-flop circuits each consisting of two mutually controlling Tubes are used in a circuit known per se. 58. Transmission system according to claim 57, characterized in that in the toggle switch elements a double triode is used each. 59. Transmission system according to claim 22, characterized in that the synchronization of the line finder oscillator is carried out by the signal pulses themselves. 60. Transmission system according to claim 22, characterized in that the synchronization of the line finder oscillator by the main oscillator controlling the distributor he follows. In addition 5 sheets of drawings © 9536 7.54