JPS5834988B2 - Yobidashi Shingo Teishi Hoshiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stopping a ringing signal in an electronic exchange using an electronic switch in a communication path.

In general, electronic exchanges that use electronic switches such as thyristors in the call path differ from regular exchanges in that they send a high-level ringing signal (usually an AC signal of 16 Hz) for ringing the bell to the telephone of the called party via the electronic switch. Since this is not possible, a calling signal sending circuit is provided on each line circuit side.

This ringing signal sending circuit is started by an activation signal from the central control unit that is sent at the same time as the call path switch on the receiving side is closed, and continuously supplies a 16z AC signal as a ringing signal to the telephone set. It is something to do.

Therefore, the transmission of the paging signal needs to be stopped when the call is canceled between when the subscriber on the called side responds and when the subscriber on the called side responds.

However, the subscriber circuit has a circuit that detects on-hook and off-hook states of the subscriber in order to detect outgoing calls, so if the called subscriber answers, the off-hook state can be detected by the above circuit, which poses a problem. There isn't.

On the other hand, if the call is canceled before the subscriber on the called side answers, for example, if the caller abandons the call (hanging up the phone during the call), or after a certain period of time after the call starts. If the subscriber on the called side does not respond after the elapsed time, the trunk side disconnects the call path current on the called side, so this can be detected on the subscriber circuit side. Simply inserting an impedance element in series with the supply path increases loss during communication, which is not preferable.

This also requires care when connecting impedance elements in parallel.

The present invention has been made in view of the above points, and a first object of the present invention is to detect the discontinuation of a call using a resistive element connected to a current supply path of a line circuit without increasing call loss. Ring signal stop (stop ring signal),
There is a method to provide.

A second object of the invention is to provide a ringing signal stopping system which also detects the called party's response and stops the ringing signal.

The present invention will be described in detail below based on the drawings.

An example is shown in FIG.

In FIG. 1, numeral 1 indicates a receiving side (called party) telephone, SW is a communication path switch, IOT is an extension trunk, LC is a line circuit, and TR8 is a calling signal sending circuit.

First, when the caller finishes dialing, the central controller CC
(not shown) uses this information to close a communication path between the IOT and the originating subscriber, and a communication path between the IOT and the terminating subscriber.

The communication path on the receiving side is established by applying a trunk activation signal from CC to terminal 81 to make transistor TR conductive.

Next, the terminal G1 of the communication path switch SW. When a switch activation bone is given to G2 and the communication path switch SW is made conductive,
The communication path current is the power supply E2 diode D9 of the line circuit LC.
- Point B - Secondary winding of transformer T1 - Point A - Communication path switch 5W - t - Transistor TR, - Resistor R6 - Ground.

The 1H transistor TR3 is a constant current circuit, and its current value is approximately VF, /R5 (where vE is the voltage across the resistor R6).

On the other hand, the current flowing through the resistor R5 is (R3-R2)/R2, and if VB/Rs>>(R3-R2)/R2, most of the current is supplied from the R2 power source.

Therefore, the potential at point A is approximately the R2 potential.

Since the winding resistance of the transformer T□ is very small, the potential at point B, which is the detection point, is also approximately the R2 potential.

Here, the Zener voltage of Zener diode D1o is R2
If a value larger than R3 is selected, no current will flow to the base of the detection transistor TR.

The central controller CC provides a signal to the 16 Hz activation terminal upon activation of the communication path.

For this reason, the flip-flop FF is set, and the point C is
It becomes XH “level, game 1- G1 works and transformer T
2 is supplied with an IKHz pulse signal.

This pulse signal is rectified and makes the SCR conductive, so the calling signal (16Hz) is passed through the SCR to the capacitor C1 - resistor R8 - telephone equipment - primary side of lance T1 - resistor R1 -
The signal flows through the ground path and rings the bell of the called party's telephone equipment.

In this state, that is, while the caller is picking up the receiver, I
Point D of the OT receives the current supply from the R3 power supply and is at a high potential, but when the caller hangs up, the D point receives current supply from the R2 power supply of the caller's line circuit (not shown). The potential becomes low.

The potential at point D is detected by the detector DCT, and the handset-up status is displayed on terminal D2, so this is monitored by CC, and when the caller hangs up the handset during a call, terminals R1 and R2 are detected. A heli-set signal is sent, transistors TR4, TR5, and TR6 are turned off, and the communication path current is cut off.

When the communication path current is cut off, point B is connected to power source E by resistor R2.
3, the potential is higher than R2, and a current flows through the path from power source E3 to resistor R, 2 to point B to Zener diode DIO to resistor R8-1 to transistor TR1.

Therefore, TR□ becomes conductive and its collector becomes "L" level, resetting the flip-flop FF.

At that point, point C becomes "L" level, gate G output becomes "L&H" level, the I KHz pulse signal is no longer transmitted to transformer T2, the SCR gate signal disappears, and SCR When the current of the ringing signal flowing through the terminal becomes equal to or less than the holding current, the sending of the ringing signal is stopped.

If the called party does not respond even after a certain period of time has elapsed after the start of the call, the terminals R1 and R2 send a heliset signal and similarly stop sending out the call signal.

If the called party then picks up the receiver and answers, the ringing signal is stopped in a manner well known in the art.

That is, the power supply E1-resistance R1 in the line circuit on the called side
Diode D, -t-lance T1 - called telephone equipment -
Current flows through the path of 1-lance T1-resistor R1-earth.

This current raises the potential at point E, and a current flows through the path of point E - Zener diode D6 - resistor R, 3 - transistor TR3, and TR3 becomes conductive, but as a result, the collector of TR3 goes to the XXL" level, and the flip-flop FF Since it is reset, the sending of the calling signal (16Hz) is stopped.

Next, FIG. 2 shows another embodiment.

The main difference of this embodiment from the embodiment shown in FIG. A switching transistor TR2 is inserted and connected, and TR2
The conduction and non-conduction of the transistor TR3 are controlled by a signal obtained from the collector of the transistor TR3.

The switching transistor TR2 is in a conductive state while the called party hangs up the handset, that is, when a call is received, until the called party answers.

Therefore, the operation while the calling party is activated and making a call, and the operation of stopping the sending of a ringing signal when the calling party stops calling until the called party answers, are as shown in FIG. Since the operation is similar to that of , the explanation thereof will be omitted.

Next, when the called party picks up the receiver and answers, the transistor TR3 becomes conductive.

Therefore, in the current supply path to the communication path switch side of the line circuit LC, a current flows to the base of TR2 through the power supply R3-dial pulse transistor TR2-R4-TR, 3-earth path, and TR2 becomes conductive.

Therefore, the potential at point B becomes approximately R3, and current flows to the base of TR□ through the path of point B - Zener diode DIO - resistor R8 - transistor TR1 - ground, and the collector of TR1 becomes ``L'' level, resetting the FF. and stops sending out the calling signal (16Hz).

In this way, in the embodiment shown in FIG. 2, if the call is to be stopped before the called party answers, the point B is set to a high potential by the resistor R2, and when the called party answers, the transistor TR2 is used to flow the communication current. By making it conductive, point B is brought to a high potential, and the output of the detection transistor TR1 resets the flip-flop FF for sending out the calling signal, thereby stopping the calling signal.

During a call, the transistor TR2 is completely conductive, so the only resistance connected in series with the detection transistor TR1 on the subscriber circuit side is the dynamic resistance when TR2 is conductive, which is very small, so the call loss does not increase. Also, from point B to Dl
o There is no call loss on the route Rs - TR1 (because TR2 is neon, point B is grounded in terms of alternating current).

The dial pulse is transmitted by turning TR2 on and off to transmit voltage fluctuations between the power supplies E3 and 82.

In other words, when TR2 is on, point A is at approximately E3 potential,
Conversely, when TR2 is off, VE/R6>> (R3-
R2)/R2, the potential at point A becomes E2 as described above, and dial pulses can be transmitted.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an electronic exchange used to explain one embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of an electronic exchange used to explain another embodiment of the present invention. . Place: Receiving side telephone, LC: Line circuit, TR8: Calling signal sending circuit, SW:
...Call path switch, IOT...Extension trunk, DCT...Detector, TR□...
Detection transistor, TR2... Switching transistor for dial pulse, Dlo... Zener diode.

Claims (1)

[Scope of Claims] 1. A switching device that sends out a calling signal from a line circuit, including a first power source that supplies current to a communication path switch via a backflow blocking rectifying element and a prescribed current supply path at the time of a calling; A second power source connected to the current supply path through a resistive element and a potential at a predetermined point change when the call path current is cut off until the called party answers. A method for stopping a ringing signal, characterized in that the method comprises: a means for detecting that a ringing signal is detected and stopping transmission of a ringing signal. 2. In a switching device that sends out a calling signal from a line circuit, a first power supply that supplies current to a communication path switch via a backflow blocking rectifier and a predetermined current supply path during a call, and a first power source that supplies current to a communication path switch via a switching element and a second power supply connected to the supply path and supplying current when paper is passed; and a predetermined resistance element connected in parallel to the switching element; The system is equipped with means for detecting a change in the potential at a predetermined point when the called party answers and stopping the transmission of the calling signal.