JPS6089159A - Ring control circuit - Google Patents

Abstract

PURPOSE:To suppress a high potential noise at switching by switching the supply of a talking current to a telephone set and the supply of a call ring signal later and earlier than the switching time point at a prescribed interval. CONSTITUTION:A talking current is fed to a single telephone set 3 with the voltage Vr of a talking current supply circuit 11 via I position contacts of switches 12a, 12b. When the switches 12a, 12b are thrown to the position of contacts R, a ring signal generator 2 is connected to the telephone set 3. A high level signal is fed to an interval signal line 16 after a prescribed interval is elapsed in this case, a transistor (TR) 15 is turned on to turn on photocoupler thyristors 13, 14 thereby applying a ring signal from the generator 2 to the telephone set 3 with the voltage Vr. Moreover, the signal of a control line 16 is brought into an L level earlier by a prescribed interval from the point of time switched to the position I to turn off the TR15, thereby disconnecting the thyristors 13, 14 when the ring signal intersects the voltage Vr.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to telephone exchange subscriber circuitry, and more particularly to ring control circuitry for controlling the provision of single telephone ring ring signals.

Conventionally, relays have been used to control ring intervals when a single telephone calls in a telephone exchange subscriber circuit. Therefore, when adopting a configuration in which the relay switching timing is intermittent so that it is unrelated to the ring waveform, the ring terminal may be connected or disconnected when the potential is high, which causes high pressure noise and adversely affects other electronic circuits. may be affected.

In addition, even if the relay is switched on and off using a signal synchronized with the ring waveform, the same problem as above may occur because the relay operation time is slow. so that it can swing only to the potential or lower potential,
If the relay is turned on and off after detecting that the potential has become the same as the reference potential, the above-mentioned drawbacks can be reduced, but this may reduce the efficiency of the ring signal generation circuit or cause the reference potential and the ring waveform to become the same potential. This method has drawbacks such as the need for a circuit to detect the point.

It is an object of the present invention to solve the above-mentioned drawbacks of reducing the efficiency of the ring generation circuit and requiring a circuit for detecting the point where the reference potential and the ring waveform become the same potential, while at the same time An object of the present invention is to provide a ring control circuit capable of suppressing high-potential noise.

In order to achieve the above object, a ring control circuit according to the present invention connects in series a communication current supply circuit and a pair of photocoupler thyristors whose anodes and cathodes are connected in reverse to each other. a paging ring supply circuit that performs on/off control of a pair of photocoupler thyristors and sends out a paging ring signal of the ring signal generator when the pair of photocoupler thyristors is turned on; and an output of the speech current supply circuit and the paging ring supply circuit. and a switch for switching the output to the individual telephone set, and when switching the switch to the output of the calling ring supply circuit, after a predetermined interval, the pair of photocoupler switches are turned on and the call ring is switched on. A signal is sent to the individual telephone, the pair of photocoupler thyristors are turned off, and after a predetermined interval, the switch is switched to the output of the communication current supply circuit.

According to the above structure, the object of the present invention can be completely achieved.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a ring control circuit according to the present invention, and is a partial block diagram of a telephone exchange subscriber circuit. In the figure, 1 is a part of the subscriber circuit. Single phone 3
is connected to the communication current supply circuit 11 through the communication current supply path 17 via the contacts on the 1 side of the switching devices 12a and 12b.

It is also connected to the calling ring supply circuit through the ring supply path 18 via the contacts on the switch 123 and 12bOR side. The DC bias value of the talking current output from the talking current supply circuit 11 to the talking current supply path 17 is Vr. The ring supply circuit for calling is a series circuit of the ring signal generator 2 and a pair of photocoupler thyristors 13 and 14 whose anodes and cathodes are reversely connected to each other, and the pair of photocoupler thyristors 13 and 14 are controlled on/off by a ring interval control signal. It consists of a transistor 15.

The ring signal generator 2 generates an AC signal that swings at the same voltage Vr as the DC bias voltage of the communication current supply circuit 11. Each photodiode of the photocoupler thyristor 13, 14 is connected in series between the collector of the transistor 15 and the power supply vcc. Therefore, when the transistor 15 controlled by the ring interval control signal turns on and off, each photodiode blinks accordingly, and each photothyristor of the photocube 2 thyristors 13 and 14 also turns on and off. 19 is a resistor and a capacitor for preventing thyristor malfunction.

FIG. 2 is a waveform diagram for explaining the operation of each part in FIG. 1. In the figure, (a) shows a switch 12a.

12b, a high level indicates a state in which the independent telephone 3 and the ring ring supply circuit R side are connected, and a low level indicates a state in which the independent telephone 3 and the call current supply circuit 11 are connected. There is. (bl is a signal on the ring interval control line 16, which becomes high level after a certain interval of 1° when the standalone telephone 3 is switched to the calling ring supply circuit R side, and the standalone telephone 3 becomes 1° as shown in the figure. It becomes low level a certain time t2 earlier than the time when it is switched to the side. (cl indicates the output waveform of the ring signal generator 2, and (di indicates the waveform applied to the independent telephone set 3).

When the standalone telephone 3 receives a call in the idle state, the switching devices 12a and 12b switch to the starting point Il of the interval t1.
l Periodically switches to the R side at 1 o'clock and to the 1 side at 12 o'clock, the end point of the interval tz. This switch 12a, 1
1. From the switching control signal of 2b and the switching of switches 12a and 12b. The ring interval control signal, which goes high late and goes low t2 early, is supplied by a non-instruction circuit.

The interval t1 is set to be longer than the time required to switch the switches 12a and 12b, and the ring interval control line 16 is extended by t from the interval start point T1.
When the signal reaches a high level after a delay, the transistor 15 becomes conductive, and the photothyristors 13 and 14 each become conductive, so that the ring signal generator 2 sends a ringing signal to the individual telephone 3, and the ring of the individual telephone rings. At this time, the DC bias value Vr from the call current supply circuit 11 is applied to the voltage applied to the individual telephone until the interval start point T1, and the switching of the switching devices 12a and L2b is started, and just before the transistor 15 is turned on, Switch 12a
, 12b are switched to the R side at the latest, and the DC bias value Vr from the ring signal generator 2 is applied, so that the ring signal applied to the individual telephone 3 is applied from the voltage point vr. Then the interval end point T
The ring interval control signal becomes low level earlier than t2, and the transistor 15 is turned off. Assuming that td is a half cycle of the ring signal (Fig. 2 (C)), the interval t2 should be larger than (half cycle td) + (error in the operation of the switch), that is, t2≧td. It is set. When transistor 15 is turned off, the forward biased side of photocoupler thyristor 13 or 14 is turned off when the ring signal crosses DC bias voltage Vr. Of course, since the photocoupler thyristor on the reverse biased side is also turned off, the DC bias value vr of the ring signal generator 2 is held in the independent telephone set 3 before the interval end point T2. Therefore, at the time of switching, the contacts of the switches 12a and 12b reach the DC bias value Vr, so that noise is suppressed.

After the interval end point, the switches 12a and 12b are connected to the I side and the DC voltage vr is supplied from the communication current supply circuit 11.
is applied, so the ring of the standalone telephone 3 does not ring.

The allowable current of the contacts of the switches 12a and 12b may be small.

As described above in detail, the present invention does not switch the contacts of the switch with a high potential difference, so it is possible to prevent noise when the ring is disconnected and to reduce the load on the contacts of the switch, such as a relay.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a main part of a telephone exchange subscriber circuit for explaining an embodiment of a ring control circuit according to the present invention, and FIG. 2 is a waveform diagram for explaining the operation of FIG. 1. 1...Single telephone subscriber circuit partial block 2...Ring signal generator 3...Single telephone 11...Talking current supply circuit LLl, 12b...Switching device 13.14.
・Photocoupler thyristor 15 ・Transistor 16 ・Ring-in β loop control line (signal) 17 ・Talk current supply path 18 ・Ring signal supply path 19 ・Thyristor malfunction prevention circuit Patent applicant NEC Co., Ltd. Company agent Patent attorney Hisashi Inoro

Claims (1)

[Claims] A talking current supply circuit and a pair of photocoupler thyristors reversely connected to the talking current supplying circuit are connected in series, and on/off control of the pair of photocoupler thyristors is performed by a ring interval control signal, and when the pair of photocoupler thyristors is turned on, a calling ring supply circuit for sending out a calling ring signal of the ring signal generator; and a switching device for switching the output of the communication current supply circuit and the output of the calling ring supply circuit to an individual telephone; When switching to the output of the ring supply circuit for calling, after a predetermined interval, the pair of photocoupler thyristors is turned on, a ℃ ringing signal is sent to the individual telephone set, and the pair of photocoupler thyristors is turned off to a predetermined time. A ring control circuit characterized in that the switch is configured to switch the output of the communication current supply circuit after an interval of .