JPS5816829B2 - Dial rotation detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dial phase change detection method that is used to prevent dialing out of a specified number due to unauthorized dialing on a telephone. .

In other words, in order to prevent long-distance calls from local public telephones, specific local telephones, etc., if a call is made to 91011, it must be invalidated, and the first dial pulse on the exchange side is 0'' or It has a function to detect 10 pulses and disable the transmission.

Therefore, in the case of a regular dial call, the exchange operates by hooking off, sends a dial tone to the telephone when preparation is complete, and then checks the first dial pulse, that is, the dial pulse by the first finger.
If it is a number other than ``0'', it will be accepted, and if it is a number ``0'', the exchange will automatically recover.
This prevents dialing number 0 after sending the dial tone.

However, depending on the operation status of the exchange, the dialed number may be accepted as is before the dial tone is sent, and in such cases, the O
``When a call is made, the call is treated as valid, resulting in a long-distance call being completed despite the fraudulent call.

For this reason, it is necessary to detect whether or not a dial tone is being sent at the time of the first finger rotation of the dial, and at the same time, it is also necessary to detect the dial phase change itself by some means. In particular, it has been extremely difficult to actually take measures to detect dial phase changes.

In other words, in order to detect dial phase rotation mechanically, it is necessary to add more contacts to the dial, which increases the complexity of the mechanism.
This results in an increase in size, which has the disadvantage of being extremely unsuitable for practical use.

In addition, especially in public telephones, it is necessary that coins are properly inserted to pay the charge. In a system in which coins are stored one by one in a charge storage safe by operating a storage lever, the coins must be in a standby position immediately before dialing, and it is necessary to detect this.

Furthermore, if coins remain on the storage lever side of the storage safe due to the storage safe being full or due to unauthorized insertion of string-hanging coins, dialing will be blocked as it will not be possible to collect more charges. Therefore, it is also required to detect the accumulated coins directly on the storage lever.As a countermeasure for this, a light emitting element and a light receiving element are provided facing each other in the part that clamps the coin path, and the light transmission between the two is prevented. The present invention uses a coin detector that detects the presence or absence of a coin depending on the situation.The present invention has the purpose of solving the conventional problems at once by using the light emitting element for detecting coins also for detecting dial phase change. The light-emitting element in the coin detector is provided in a part that holds the coin path of the public phone, with a light-emitting element and a light-receiving element that receives the light emitted from the light-emitting element facing each other, and the telephone circuit is short-circuited when dialing. A dial phase change detection method that is extremely rational and easy to convert into an all-semiconductor type, characterized in that it is inserted into a part parallel to the short-circuit contact of the dial, and is used for both coin detection and dial phase change detection. It provides:

Hereinafter, the present invention will be explained in detail with reference to FIG. 1 and subsequent figures showing embodiments.

Figure 1 is a cross-sectional view of the coin path in a public telephone;
A coin inserted from above the coin path 1 made of a flat metal tube or the like is blocked by the storage lever 2 and waits directly above the storage lever 2, but when a charge signal arrives from the exchanger, the coin is inserted into the storage lever 2. slides to the right and drops the waiting coins into the storage safe below.

Therefore, immediately before a call is made from the telephone, it is necessary that a coin be present in the standby position, that is, directly above the storage lever 2, and at the same time, there must be no coin present directly below the storage lever 2, and both conditions must be met. For the purpose of checking, a light emitting element EL1. EL2 and a light receiving element PT1 such as a light receiving diode or a CdS cell. PT2 are provided facing each other, and the light emitting elements EL1. The light beam emitted by EL2 is transmitted to light receiving element PT1. PT2 receives light, and depending on the presence of a coin, the light receiving elements PT1 and PI3
The light receiving input of the light receiving elements EL1. The impedance of EL2 increases, that is, it becomes an OFF state, and the absence of a coin provides light receiving input, causing light receiving elements EL0. EL2
The impedance of the sensor decreases, that is, turns on, and coin detection at each position is performed based on this impedance change.

FIG. 2 is a circuit diagram of a circuit configuration to which this method is applied, and shows line terminals L1. A hook switch H8 and a dial impulse contact Di are inserted in series between L2 and the call dialing device, and an impulse contact D for dial dialing is inserted in series.
In order to prevent the intermittent sound of the loop current caused by i from being applied to the communication device, the short-circuiting contact Ds of the dial that shorts the same device is connected in parallel with the communication device. During this period, the short-circuit contact Ds is turned on.

The light-emitting element EL2 of FIG. 1 is inserted in series in a part parallel to this short-circuit contact Ds, that is, in the example shown, between the short-circuit contact Ds and the telephone line device, and when the hook switch H8 is turned on by hook-off, the light emitting element EL2 of FIG. Leading line terminal L1.
Light is emitted due to the loop current between L2 and the telephone line device, and the light beam resulting from this light emission is received by the light receiving element PT2.

Note that the light receiving element PT2 is the same as that in FIG. 1, and the other light emitting elements EL1. The light receiving element PT1 is also the same as that shown in FIG. 1.

Therefore, the loop current due to hook-off is
While the light is connected to L2, the light receiving element PT2 is turned on, and the voltage pt2 at the connection point with the resistor R1 is a low potential (hereinafter referred to as 91 L), but when the shorting contact Ds is turned on due to phase rotation of the dial, The light emitting element EL2 and subsequent elements are short-circuited, the light emission of the element EL2 disappears, the light receiving element PT2 is turned off, and the voltage vpt2 becomes a high voltage (approximately equal to the power supply V).
Hereinafter, it will be referred to as "H").

Assuming that coins are staying between the light-emitting element EL2 and the light-receiving element PT2 in FIG. 1 due to the storage safe being full or illegal insertion of string-hanging coins, the hook switch H8 in FIG. is turned on, and the loop current causes the light emitting element EL2 to emit light, but the light receiving element PT2
remains off and the voltage V, t2 is H'', so this is applied to input 1 of the NAND gate NAND1.

On the other hand, the diode D1. D2. Zener diode Z
D and capacitor C1 are connected to line terminal L1. This is to power each circuit using the line voltage from the exchange that is applied between L2 with line terminal L1 as the positive terminal, and the terminal voltage of capacitor C1 is taken out from terminal V and supplied to each circuit. , the loop current produces a voltage at terminal V,
In response to this voltage, an initial reset circuit IR8 using a differentiating circuit or the like generates a continuous output and a pulse output as "H", and applies the pulse output to the input 2 of the NAND gate NAND1.

Therefore, the AND output of the NAND gate NAND is L
This "Ll+" sets the flip-flop circuit (hereinafter referred to as FFC) FF1, gives an output of "L" to the short circuit SHT, short-circuits the impulse contact Di, and disables dialing.

Incidentally, as the short circuit SHT, a SIRISK or the like is suitable, and the SIRISK may be turned on via a transistor or the like by the output of the FFC-FF1.

Furthermore, if there is no coin staying between the light emitting element EL2 and the light receiving element PT2, the light receiving element PT2 is turned on, so that the voltage V
pt2 is LI+, and the above-mentioned shorting of the impulse contact Di is not performed.

Then, there was no coin on the light emitting element FF2 side, and the light emitting element EL
If there is no coin waiting between 1 and the light receiving element PT1, and the dial is rotated after the hook-off, the light emitting element EL2 will be dimmed by turning on the shorting contact Ds, and the light receiving element PT2 will be turned off, so the voltage vpt2 will be N. HI! This change is differentiated by the capacitor C2 and the resistor R2, and a pulse signal is given to the inverter N1, and the inverted output "L" turns on the transistor Tr1 via the resistor R3.

When the transistor Tr1 is turned on, a current flows from the power source 2 to the light emitting element EL through the resistor R4, and the emitted light is received by the light receiving element PT, which turns on and connects the resistor R6 to the light emitting element EL. The voltage Vpt1 is changed to i, $1, thereby setting FFC-FF2, and its output turns on the short circuit SHT to disable transmission.

Note that the light emitting element EL1 emits light only during the period of the pulse signal from the capacitor C2 and the resistor R2, and this check is made at the same time as the start of dial phase rotation, and the light emitting element FF1
If there is a coin next to it, FFC/FF2 will not be set and dialing will be possible.

Furthermore, since the short-circuit contact Ds is turned off by the end of the rotation of the dial, the voltage Vpt2 changes to 39+L +1, which resets FFC-FF2, but the FFC
- Since the initial reset circuit IR8 applies a reset pulse to FF1 only by hook-off after hook-on, it maintains the set state and prevents dialing until it hooks-off again.

Note that a proper dial call should be made after a dial tone is sent from the exchange, and the following circuit is provided to check this.

That is, line terminal L1. After amplifying the output of the dial tone receiving circuit DTR using a high input impedance P-wave device etc. bridge-connected to L2 by amplifier A, the waveform shaping circuit WF converts it into a pulse signal with a period corresponding to the frequency of the dial tone. This is converted using AND gate A.
It is given to input 1 of ND1.

On the other hand, due to the phase rotation of the dial, the shorting contact Ds is turned on, so as mentioned above, the light receiving element PT2 is turned off and the voltage V
Turn pt2 to "H".

This “H” is inverted by the inverter N2 and becomes “L”
This resets the counter CT, but at the same time drives a pulse generator PG such as a monostable multi-bi-break, and outputs an "H" pulse with a time width T to regulate the specified period for counting dial tone pulse signals. is generated and applied to input 2 of AND gate-1-ANDl.

Therefore, the pulse signal of the dial tone passes through the AND gate (ANDl) only during the period of time width T, and the counter CT counts this and counts the number of pulse signals corresponding to the frequency of the dial tone. Only outputs B1 to B3 are set to "Htl" at the same time, and AN
The output of the D gate AND2 is given as "HIT" to the input 1 of the NAND gate NAND2.

At this time, when the pulse output with time width T ends and changes to L'', the output of inverter 1N3 becomes HFI and is converted to NA.
Provided to input 2 of ND gate NAND2.

Therefore, if inputs 1 and 2 of the NAND gate NkND2 become ``H'' at the same time, the output becomes ``L'',
It detects that a regular dial tone is arriving at a dial phase change and produces a detection output DTD.

In addition, if the dial tone is not a regular dial tone and the frequency is different, the outputs B1 to B3 of the counter CT will be H'' at the same time.
The timing at which this occurs does not match the timing at which the output of the inverter N3 changes to H'', and the detection output DTD is not generated, thereby turning off the forced disconnection circuit ECF and preventing unauthorized transmission.

Further, this detection output TD is also used for resetting the short circuit SHT.

In addition, the configuration shown in FIG. 2 can be modified in various ways depending on the characteristics of the logic circuit used, and it goes without saying that any combination can be used depending on the conditions.

As is clear from the above explanation, according to the present invention, there is no need to add a separate mechanism to the dial, and at the same time, there is no chuck ring like a mechanical contact, and the dial functions as both a light emitting element and a light receiving element for detecting coins. Therefore, no extra elements are required, and by using all semiconductors, dial phase change detection can be performed with extremely high reliability.The entire device can be easily miniaturized, and it has great effects when applied to public telephones. .

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a sectional view of a coin path, and FIG. 2 being a circuit diagram showing the circuit configuration. 1... Coin route, ELl, EL2...
Light emitting element, PTl, PT2... Light receiving element,
...Talking circuit, Ds...Short contact.

Claims (1)

[Claims] 1. In a coin detector, a light-emitting element and a light-receiving element that receives the light emitted from the light-emitting element are provided facing each other in a part that holds the lower part of the storage lever in the coin path of the public phone. An initial reset circuit is provided that is inserted into a part parallel to the short-circuit contact of the dial that is short-circuited when dialing, and generates a pulse output when the hook-off occurs, and the accumulated coins are detected by the logical product of the pulse output and the output of the light-receiving element. On the other hand, if the accumulated coin is not detected, the output of the light receiving element detects that the light emitting element dims in accordance with the dial phase change after the hook-off, and the dial phase is changed. A dial phase rotation detection method characterized by detecting phase rotation.