JP2687705B2 - Digital transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used for a signal multiplexing control system of a data terminal device in a digital data transmission service. In particular, it relates to a dedicated line digital subscriber terminal multiplexing system in which a signal processing device on the network side and a user terminal device forming one end of a digital transmission network are connected by a digital signal train of CCITT Recommendation I.430 user / network interface.

〔Overview〕

According to the present invention, in a digital transmission system having a signal processing device for accommodating a terminal device in a bus type by using an I interface, the transmission capacity of the terminal device is flexible by using the Q bit which the user is allowed to use as an option. To enable efficient accommodation of low to high speed data.

[Conventional technology]

A conventional terminal device on the subscriber side defines a signal processing device that performs signal termination on the communication carrier (network) side that provides a digital transmission service and a specific user / network interface,
It constitutes a digital transmission network. Especially for high-speed digital leased lines, which have been actively used in recent years, 64 Kbps to 61
It provides users with high-speed data up to 44 Kbps. In this high-speed leased line service, in order to effectively use the transmission signal, as shown in FIGS. 9 and 10, the multiplexing device is provided to the user side in order to multiplex the data rate corresponding to the data such as telephone, image and file. Place (hereinafter referred to as TDM), P
BX, video conferencing equipment, FAX, data terminal, etc. are accommodated in a high-speed data stream in a time division multiplexed manner for efficient data transmission.

[Problems to be solved by the invention]

In such a conventional system, an expensive TDM device has to be arranged in order to effectively use the transmission signal. On the other hand, the introduction cost of the TDM device with relatively low speed data of about 64 Kbps bulges from the viewpoint of utilization efficiency, and development of an inexpensive device has been desired.

The present invention uses a I / O interface (192 Kbps I.430) standardized by CCITT (International Telegraph and Telephone Advisory Committee) as a user / network interface of 128 Kbps or less to connect a terminal device on the subscriber side to a bus type. By accommodating more than one, and using the Q bit that the user is allowed to use as an option in this Recommendation, the transmission capacity of eight terminals connected to the bus can be changed flexibly to efficiently accommodate low-speed data to high-speed data. It is an object of the present invention to provide an economical digital transmission method that can be performed.

[Means for solving the problem]

The present invention relates to a signal processing device on the side of a telecommunications carrier, which is connected to each of opposite ends via a leased line network, and CCITT recommendation.
In a digital transmission system comprising a plurality of terminal devices on the user side connected to each of the signal processing devices via a digital transmission network through which a digital signal train of a user / network interface conforming to I.430 passes, A main terminal multiplex control circuit inserted between a signal processing device connected to one end of the leased line network and a terminal device accommodated in the signal processing device, and a signal connected to the opposite end It is provided with a slave terminal multiplex control circuit inserted between the processing device and a terminal device accommodated in this signal processing device, and the above-mentioned main terminal multiplex control circuit is allowed to be used by the user as an option by CCITT Recommendation I.430. Using the Q bit that is set, each terminal device connected to the main terminal multiplex control device is notified of the transmission rate and transmission timing set in the terminal device, and the control is performed. The slave terminal multiplex control circuit, the slave terminal multiplex control circuit is connected to the slave terminal multiplex control device based on the control information notified from the master terminal multiplex control circuit. A means for notifying the terminal device of the transmission rate and the transmission timing set in the terminal device by the Q bit, each of the terminal devices notifying by the Q bit from the main terminal multiplex control circuit or the slave terminal multiplex control device. It is characterized by including a terminal control circuit for controlling the transmission rate and the transmission timing of the terminal device based on the above.

The main terminal multiplex control circuit sets a transmission rate for a terminal device connected to its own circuit and a terminal device connected to the slave terminal multiplex control circuit, a sending timing, and a Q bit for setting an identification number signal for identifying this terminal device. A setting processing unit and a first Q that multiplexes the setting contents of the Q bit setting processing unit with the Q bit of the I.430 signal sent from the signal processing device to which the own circuit is connected to the terminal device connected to the own circuit. A second Q that multiplexes the setting contents of the bit multiplexing unit and the Q bit setting processing unit into the Q bits of the I.430 signal sent from the terminal device connected to the own circuit to the terminal device connected to the own circuit.
It is desirable to include a bit multiplexer.

The slave terminal multiplex control circuit includes a Q bit separation unit that separates the Q bit of the I.430 signal from the signal processing device to which the self circuit is connected, and a terminal that is connected to the self circuit based on the separated Q bit. Q which sets the transmission rate to the device, the transmission timing and the identification number signal for identifying this terminal device
It is desirable to include a bit setting processing unit and a Q bit multiplexing unit that multiplexes the setting contents of the Q bit setting processing unit with the Q bits of the I.430 signal sent to the terminal device connected to the own circuit.

The terminal control circuit is separated by a Q bit separation unit that separates Q bits from the I.430 signal coming from the slave terminal multiplexing control circuit, and a message analysis unit that analyzes control information from the separated Q bits. An identification number determination unit that determines whether or not the control information based on the Q bit is for the own circuit from the identification number signal included in the Q bit, an analysis result of the message analysis unit, and a determination result of the identification number determination unit. According to the instruction of the multiplex sending control unit that sets the transmission speed and the transmission timing of the terminal device to which the own circuit belongs, and the I.
430 signal and B of I.430 signal transmitted from the terminal device
It is desirable to include a B channel / D channel processing unit that controls transmission of channels and D channels.

[Action]

If the TDM device is used for relatively low speed data of about 64 Kbps, the utilization efficiency is low. Therefore, a plurality of terminal devices on the subscriber side can be accommodated by using the I interface according to the CCITT recommendation, and the transmission capacity of each terminal device can be flexibly changed by using the Q bit which is permitted to use the option according to this recommendation. Performs multiple control.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a network system configuration diagram according to this embodiment. The terminal multiplex control circuit of the present invention is a terminal for efficiently accommodating signal processing devices 108 and 109 for terminating the network side of a communication carrier providing an I.430 interface transmission service, digital telephones, data terminals, and low-speed data terminals.・ Terminal devices 104 to 107 such as adapters
It is an example of a usage mode in which data is transmitted to a terminal device facing the network of a telecommunications carrier by arranging it with (a maximum of 8 terminals).

2 and 3 show a main terminal multiplexing control circuit 101, respectively.
3 is a block diagram of a main signal processing unit of a slave terminal multiplexing control circuit 102. FIG. The main terminal multiplex control circuit 101 is in the position of the main control in the sense of commanding and controlling the signal processing to the slave terminal multiplex control circuit 102. It is in the position of control.

As shown in FIG. 1, this embodiment complies with CCITT Recommendation I.430 and signal processing devices 108 and 109 on the side of the communication carrier, which are connected to respective opposite ends through a leased line network 110. A plurality of terminal devices 104 to 107 on the user side connected to each of the signal processing devices via a digital transmission network through which a digital signal train of a user / network interface passes, and a feature of the present invention are further provided. As means, a signal processing device 108 connected to one end of the leased line network 110 and a terminal device 104 connected to the signal processing device 108.
Main terminal multiplex control circuit 101 inserted between
And a signal processing device 109 connected to the other end opposite to each other and terminal devices 106 and 10 connected to the signal processing device 109.
7, and the slave terminal multiplex control circuit 102 inserted between
Each of the terminal devices 104 to 107 includes a terminal control circuit. Here, as shown in FIG. 2, the main terminal multiplex control circuit
Reference numeral 101 denotes terminal devices 104 and 105 connected to its own circuit and terminal devices 106 and 10 connected to a slave terminal multiplex control circuit 102.
A storage having a Q-bit setting processing unit 201 for setting a transmission rate, a transmission timing for 7, and an identification number signal for identifying the terminal devices 104 to 107, and a nonvolatile memory for storing the contents set by the Q-bit setting processing unit 201. Part 203,
I.430 frame terminators 206 and 211 for bipolar / unipolar conversion and frame synchronization of I.430 signal, Q for separating Q bit in multi-frame FA bit of I.430 signal
Bit demultiplexing units 207 and 212, Q bit multiplexing units 204 and 209 that multiplex the signal control message of the Q bit setting processing unit 201 into an I.430 signal, I.430 frame generating units 205 and 210 that transmit an I.430 signal, A message determination unit 20 for determining the correctness of the signal control message returned from the slave terminal multiplex control circuit 102 and the terminal devices 104 and 105 connected to the own circuit.
8 and 213 and a remote console 202 to which a control console 103, which is a means for controlling the Q-bit setting processing unit 201 from the outside, is connected, and the slave terminal multiplex control circuit 102, as shown in FIG. Terminal multiplexing control circuit 1
To the Q-bit setting processing unit 301, which sets the transmission speed, the transmission timing, and the identification number signal for identifying the terminal device 106 and 107 connected to the own circuit based on the 01 command, to the Q-bit setting processing unit 301. Message separation unit 307 for transmitting the signal control message of I.430, a storage unit 302 having a non-volatile memory for storing the extracted signal control message, and an I.430 frame termination for performing bipolar / unipolar conversion of the I.430 signal and frame synchronization. Parts 305 and 31
0, Q bit separating units 306 and 311 for separating Q bits in the multi-frame FA bit of the I.430 signal, Q for multiplexing the signal control message of the Q bit setting processing unit 301 into the I.430 signal
Bit multiplexers 303 and 308, I.430 transmitting I.430 signal
The frame generation units 304 and 309, a message determination unit 312 for determining the correctness of the signal control message returned from the terminal device connected to its own circuit, and the terminal control circuit, as shown in FIG. I.430 signal bipolar
An I.430 frame terminating unit 401 that performs unipolar conversion and frame synchronization, a Q bit separating unit 402 that separates a message of setting information of a terminal device to which the own circuit belongs from a multi-frame FA bit of an I.430 signal, this separated A message analysis unit 403 that decodes a message, this message analysis unit 403
The multiplex transmission control unit 404 that controls the transmission to the terminal device to which the own circuit belongs and the signal processing according to the determination result of 1., and the B and D channels of the I.430 signal according to the instruction of the multiplex transmission control unit 404. B channel / D channel processing units 405 and 406 that perform transmission control, an identification number determination unit 407 that determines and compares the identification number indicated by the identification number signal added to the message with the identification number of the terminal device to which the own circuit belongs, and its own circuit Message analyzer for the terminal multiplex control circuit corresponding to
Message response unit 40 that returns the setting information decrypted in 403
8, an identification number setting unit 409 for giving the identification number of the terminal device to which the own circuit belongs, a Q-bit multiplexing unit 410 for synthesizing as Q bits in the multi-frame FA bits, and an I.430 frame generating unit for transmitting as an I.430 signal With 411.

Next, the function and operation of the main terminal multiplexing control circuit 101 will be described. The right part of FIG. 2 shows a connection interface with the signal processing device 108, and the left part shows an interface with the terminal devices 104 and 105. The Q-bit setting processing unit 201, which is the core of the operation of the present invention, generates a control message to the terminal devices 104 and 105 to be connected and a control message to the slave terminal multiplex control circuit 102 to be connected oppositely, CCITT Recommendation I It has the function of transmitting and receiving to the user's option bits Q1 to Q2 specified by the .430 interface. According to I.430 recommendation, shown in Figure 6.
As shown in the table, the FA bit of the I.430 interface frame has Q2, Q3, Q4 and 4 bits for every 5 multiframes starting from the Q1 bit located on the 20 multiframes with M bits on the same frame. 5ms (1 frame 250μs x
20 multi) can be transmitted every.

The present invention is configured to transfer the message shown in FIG. 5 to these 4 bits. The communication control procedure necessary for sending and receiving this message can be easily realized by using the basic procedure or HDLC procedure which has been widely put into practical use. The message shown in FIG. 5 is the identification number information for identifying the terminal device, the speed class setting information for determining the communication capacity to be used by each terminal device, and the timing at which the terminal device sends the signal processing device. For sending position setting information that determines the setting information, a control command for updating the setting information for these messages, a command for transferring the setting information of itself to the terminal device or the slave terminal multiplex control circuit 102, and an alarm monitoring purpose. And maintenance information.

The setting of this message can be set by the main terminal multiplexing control circuit 101 itself, or can be set remotely from the external control console 103 or the like via the remote interface 202. Further, the message information once set is stored in the storage unit 203 composed of a non-volatile memory, and resetting at the time of power off is unnecessary.

Hereinafter, the message to the terminal device is "message T",
The message to the slave terminal multiplex control circuit 102 will be referred to as "message M". The message T for each of the terminal devices 104 and 105 is multiplexed by the Q-bit multiplexing unit 204 into Q bits of the signal sequence to be transmitted to the terminal devices 104 and 105.
The I.430 frame generation unit 205 includes a unit for generating a frame specified by I.430 and a unipolar / bipolar conversion unit, and outputs it as an I.430 transmission signal 23 to the terminal devices 104 and 105. The I.430 frame termination unit 206 is the terminal device 104.
The I.430 received signal 24 from the signals 105 and 105 is converted into a unipolar signal by the bipolar / unipolar conversion unit, and the frame timing pulse is detected by the frame synchronization unit. This timing pulse identifies the Q bit in the FA bit, and the Q bit separation unit
Separate at 207. This Q bit contains the terminal device 104 and
Message response information is returned from the terminal control circuit on the 105 side, and this response information and the information set for the corresponding terminal device by the Q-bit setting processing unit 201 are sent according to the command of the Q-bit setting processing unit 201. Message to
The message determination unit 208 determines whether or not is processed correctly. In the above case, control is performed so as to send a command such as resetting the setting information or stopping transmission of the corresponding terminal device.

On the other hand, the terminal device setting information to the slave terminal multiplex control circuit 102 is the Q bit multiplex section 20 as the message M as in the above.
It is multiplexed with Q bits at 9. I.430 Frame generator 210
Is a means for generating a frame specified by I.430 and a unipolar / bipolar converter,
Output as I.430 transmission signal 22. I.430 frame end
At 211, the I.430 received signal 21 from the signal processing device is bipolar-unipolar converted as described above, and a frame timing pulse is detected. With this timing pulse, the Q bit in the FA bit is separated by the Q bit separating unit 212. This Q
The message response information from the slave terminal multiplex control circuit 102 is returned to the bit, and this response information and the information set in the slave terminal multiplex control circuit 102 by the Q bit setting processing unit 201 are subjected to the Q bit setting processing. The message determination unit 213 determines whether or not the message to the slave terminal multiplexing control circuit 102 is correctly processed according to the command of the unit 201. In the case of abnormality, it is controlled to send a command such as resetting the setting information.

The right part of FIG. 3 shows the connection interface with the terminal devices 106 and 107, and the left part shows the interface with the signal processing device 109. Q-bit control processing unit 301, storage unit 302, Q
Bit multiplexers 303 and 308 and I.430 frame generator 304
And 309, I.430 frame terminators 305 and 310, and Q.
Each of bit demultiplexing sections 306 and 311 and message determining section 312 has the same function as each of main terminal multiplexing control circuit 101. The message demultiplexing unit 307 receives the I.430 received signal 34 from the signal processing device 109 as the message M for signal processing from the main terminal multiplexing control circuit 101 to the slave terminal multiplexing control circuit 102.
It is separated from the Q bit of the multi-frame FA bit. This message M is initial setting information and the like necessary for transmitting the necessary message T to the terminal devices 106 and 107 to which the slave terminal multiplexing control circuit 102 is connected. On the other hand, this message M is returned to the main terminal multiplexing control circuit 101 as message response information through the Q-bit multiplexing unit 303. This message can be used as it is by using the ID information in the slave terminal multiplex control circuit in the message format shown in FIG.

FIG. 4 shows a terminal control circuit added in the terminal device.

Main terminal multiplex control circuit 101 or slave terminal multiplex control circuit 102
The I.430 received signal 41 from the I.430 frame termination unit 401 and the Q bit separation unit 402 separates the message T for the terminal device from the Q bits of the multi-frame FA, and the speed class determination unit in the message analysis unit 403. Determines the transmission capacity of the terminal device, and the transmission position determination unit determines the transmission timing of the terminal device. In addition, the command determination unit detects control information such as update of setting information and stop of signal transmission. These determination results are input to the multiplex transmission control unit 404 as a control signal, and the B channel / D channel processing units 405 and 406 selectively process the corresponding channels. That is, the I.430 received signal 41 is selectively transmitted to the terminal device output signal 43 by the B channel / D channel processing unit 405 as a meaningful channel only for the corresponding channel of the terminal. The state of this signal conversion is shown in FIG. Similarly, the B channel / D channel processing unit 406 receives the received signal 44 from the main signal processing unit of the terminal according to I.430.
Transmit to the designated B channel or D channel of the frame. This is shown in FIG. Identification number determination unit 407
Compares the identification number preset in each terminal device with the identification number information of the message T in order to determine whether or not the message has been transferred to the message T itself, and performs control by command information only when they match. Are treated like. On the other hand, for the control information by the multiplex transmission control unit 404, the message response unit 408 generates a return signal as response information to the terminal multiplex control circuit, the terminal identification number from the identification number setting unit 409 is added, and the Q bit multiplex unit is added. In 410, it is multiplexed as Q bit of multi-frame FA, and I.430 frame generator 411 adds a frame sync pulse to unipolar
It is configured to perform bipolar conversion and output it as an I.430 transmission signal 42 to the terminal multiplexing circuit section.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention does not require an expensive TDM device in order to effectively use a terminal of a leased line that is relatively inflexible, and does not require a plurality of subscriber terminals for one signal processing device. It is possible to connect all at once, and it is possible to flexibly support low-speed data and high-speed data, and it is possible to easily implement terminal-specified communication and priority communication, and it is possible to use the leased line as a simple private exchange network, making it more flexible and economical. This has the effect of realizing a multiplex control system for various digital subscriber terminals.

[Brief description of the drawings]

FIG. 1 is a network system configuration diagram of an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the main terminal multiplexing control circuit shown in FIG. FIG. 3 is a block diagram showing the configuration of the slave terminal multiplex control circuit shown in FIG. FIG. 4 is a block diagram showing a configuration of a terminal control circuit added in the terminal device shown in FIG. FIG. 5 is a configuration diagram of a control message transmitted and received between the terminal device and the terminal multiplex control circuit. Figure 6 is a frame format diagram according to CCITT Recommendation I.430. FIG. 7 is a time chart showing how a corresponding signal contained in an I.430 signal is converted into a signal for the main signal processing unit of the terminal device. Fig. 8 shows the signal from the terminal device, which specifies the I.430 signal B
7 is a time chart showing an example of conversion into a channel or a D channel. FIG. 9 is a conventional network system configuration diagram. FIG. 10 is a format diagram of a frame used in the conventional example. 21, 24, 31, 34, 41 ... I.430 received signal, 22, 23, 32, 3
3, 42 ... I.430 transmission signal, 43 ... Terminal device output signal, 44 ... Reception signal, 101 ... Main terminal multiplex control circuit, 102 ... Slave terminal multiplex control circuit, 103 ... Control console, 104-107 ... Terminal device ( T
E), 108, 109 ... Signal processing device (NT), 110 ... Dedicated line network,
201, 301 ... Q bit setting processing unit, 202 ... Remote interface, 203, 302 ... Storage unit, 204, 209, 303, 308, 41
0 ... Q bit multiplexing unit, 205, 210, 304, 309, 411 ... I.430
Frame generating section, 206, 211, 305, 310, 401 ... I.430 Frame terminating section, 207, 212, 306, 311, 402 ... Q bit separating section, 208, 213, 312 ... Message judging section, 307 ... Message separating section 403 ... Message analysis section, 404 ... Multiplex transmission control section, 405, 406 ... B channel / D channel processing section, 407 ...
Identification number determination unit, 408 ... Message response unit, 409 ... Identification number setting unit.

Claims (4)

(57) [Claims] 1. A telecommunications carrier-side signal processing device connected to each of the opposite ends via a leased line network, and CCITT recommendation.
In a digital transmission system comprising a plurality of terminal devices on the user side connected to each of the signal processing devices via a digital transmission network through which a digital signal train of a user / network interface conforming to I.430 passes, A main terminal multiplex control circuit inserted between a signal processing device connected to one end of the leased line network and a terminal device accommodated in the signal processing device, and a signal connected to the opposite end It is provided with a slave terminal multiplex control circuit inserted between the processing device and a terminal device accommodated in this signal processing device, and the above-mentioned main terminal multiplex control circuit is allowed to be optional by the user according to CCITT Recommendation I.430. Using the Q bit that is set, each terminal device connected to the main terminal multiplex control device is notified of the transmission rate and transmission timing set in the terminal device, and the control is performed. Means for notifying information to the slave terminal multiplex control circuit, wherein the slave terminal multiplex control circuit is connected to the slave terminal multiplex control device based on the control information notified from the master terminal multiplex control circuit. A means for notifying the terminal device of the transmission rate and the transmission timing set in the terminal device by Q bit, each of the terminal devices being notified by the Q bit from the main terminal multiplex control circuit or the slave terminal multiplex control device. A digital transmission system characterized by including a terminal control circuit for controlling the transmission speed and transmission timing of the terminal device based on the above. 2. The main terminal multiplex control circuit is provided with a terminal device connected to its own circuit and a terminal device connected to the slave terminal multiplex control circuit, a transmission rate, a transmission timing, and an identification number signal for identifying this terminal device. And the setting contents of this Q-bit setting processing unit are multiplexed into the Q-bit of the I.430 signal sent from the signal processing device to which the own circuit is connected to the terminal device connected to the own circuit. The first Q-bit multiplexing unit and the setting contents of the Q-bit setting processing unit are sent from the terminal device connected to the own circuit to the terminal device connected to the own circuit.
The digital transmission system according to claim 1, further comprising a second Q-bit multiplexing unit that multiplexes the Q-bits of the I.430 signal. 3. The slave terminal multiplex control circuit comprises: a Q of an I.430 signal from a signal processing device to which the sub circuit is connected.
A Q-bit separation unit that separates bits, and a Q-bit setting processing unit that sets a transmission rate, a transmission timing, and an identification number signal for identifying the terminal device connected to its own circuit based on the separated Q bits The digital transmission system according to claim 1, further comprising: a Q-bit multiplexing unit that multiplexes the setting contents of the Q-bit setting processing unit with the Q bits of the I.430 signal sent to the terminal device connected to the own circuit. 4. The terminal control circuit receives Q from I.430 signals coming from the slave terminal multiplex control circuit.
A Q-bit separation unit that separates the bits, a message analysis unit that analyzes control information from the separated Q bits, and an identification number signal included in the separated Q bits from the Q
An identification number determination unit that determines whether or not the bit control information is for the own circuit, and a transmission rate of the terminal device to which the own circuit belongs according to the analysis result of the message analysis unit and the determination result of the identification number determination unit. And a multiplex transmission control unit for setting transmission timing, and an I.430 signal to the terminal device to which the own circuit belongs and an I.4 signal transmitted from the terminal device according to an instruction of the multiplex transmission control unit.
The digital transmission system according to claim 3, further comprising a B channel / D channel processing unit that controls transmission of 30 channels of B channel and D channel.