JPH0681183B2 - Ringer signal transmission method - Google Patents

Description

[Detailed Description of the Invention] Outline The present invention relates to a ringer signal transmission method for transmitting a ringer signal to a subscriber terminal, and eliminates the load on the ringer device when a ringer signal is not transmitted by a relay provided in a common part of each subscriber line. In the ringer signal transmission method in which a ringer signal is transmitted from a ringer device to a plurality of subscriber terminals, a contact of a relay and a operation of the contact are controlled in a common part of a plurality of subscriber lines. A contact control circuit is provided, and the contact provided in the common portion is controlled to be continuously closed by the contact control circuit during the ringer signal transmission, and the contact is opened when the ringer signal is not transmitted.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ringer signal transmission system for transmitting a ringer signal to a subscriber terminal.

One of the functions of the subscriber circuit used in the digital exchange is a ringer signal sending function for ringing the bell of a telephone (subscriber terminal). 16 generated from Ringer generator
The AC signal of H _z is superposed on the DC signal, the relay contacts are turned on and off, and the signal is sent so as to sound at 1 second intervals, for example, at 2 second intervals. When the called party goes off-hook (when the handset is picked up), a direct current flows through the subscriber line, which is detected by the ring trip monitoring circuit and the sending of the calling signal is stopped.

As described above, the ringer signal transmission circuit is connected to a monitoring circuit for detecting on-hook (a state in which the handset is hung) and off-hook of the telephone, and the ringer transmission circuit is not adversely affected by these circuits. It is necessary to do so.

2. Description of the Related Art FIG. 6 shows a block circuit diagram of a conventional ringer signal transmission system.

Reference numeral 11 is a telephone, 16 is a ringer device that superimposes an AC signal from the ringer generator 17 on a DC voltage (-48V) and sends it out, 18
Is a sending resistor, 20 and 22 are contacts of the ringer relay 23, 24 is a power supply circuit for supplying a call current to the telephone 11, 26 is a telephone 11
This is a ring trip monitoring circuit that monitors the on-hook and off-hook states of the.

When the ringer signal is sent (during ringing), the contacts 20 and 22 of the ringer relay 23 are closed to the 1 side shown in FIG. 6, and the ringer signal sent from the ringer device 16 is sent to the sending resistor 18-contact 20-join. Telephone line R-Bell circuit in telephone 11-
Subscriber line T-contact 22-flows through the earth path and rings the bell of telephone 11. When the telephone 11 goes off-hook, a direct current flows, and this direct current is sent to the ring trip monitoring circuit.
Detected at 26, the contacts 20 and 22 are tilted to the 0 side and the bell of the telephone 11 is stopped.

When the ringer signal is not sent, the contact 20 of the ringer relay 23,
22 is closed to the 0 side in FIG. 6, and the subscriber line R and the ringer device 16 are disconnected. Further, a ring trip monitor circuit 26 is connected to the transmission resistor 18, and this ring trip monitor circuit 26 includes an RC low pass filter composed of a capacitor (C) and a resistor (R). Working as. Since the subscriber line is connected to 1000 to 5000 lines to one ringer device 16, the impedances of a large number of ring trip monitoring circuits 26 are connected to the ringer device 16 in parallel.

Problems to be Solved by the Invention However, in the ringer signal transmission method as described above, the ring trip monitoring circuit includes the RC low pass filter,
Since this acts as a load on the ringer device, there is a problem in that wasteful power loss is large.

In order to eliminate such a problem, a ringer signal transmission system as shown in FIG. 7 can be considered.

FIG. 7 shows a block circuit diagram of a ringer signal transmission system in the case where a relay contact is provided for each subscriber line,
This is a system in which a relay contact 36 is provided for each subscriber line as compared with the conventional example of FIG. Since the components other than the contact 36 are the same as those in FIG. 6, the description thereof will be omitted. The ring trip monitoring circuit 26 can be disconnected from the ringer device 16 by opening the contact 36 when the ringer signal is not sent, but one subscriber line requires three relay contacts. Furthermore, when actually mounted, a 3-contact relay is not commercially available as a standard product, and two 4-contact or 2-contact relays are used, which is poor in practical use in terms of mounting area and cost. There was a problem.

The present invention has been made in view of the above circumstances, and an object of the present invention is to eliminate a load of a ringer device when a ringer is not delivered by a relay provided in a common part of each subscriber line. It is to provide a signal transmission method.

Means for Solving the Problems FIG. 1 shows a block diagram of the principle of the present invention. In a ringer signal transmission system for transmitting a ringer signal from a ringer device 16 to a plurality of subscriber terminals 10, a relay contact 12 is provided at a common part of a plurality of subscriber lines, and a contact control circuit 14 for controlling the operation of the contact 12. To provide. Then, during transmission of the ringer signal, the contact 12 provided in the common portion is connected to the contact control circuit 14
Is controlled so as to be closed continuously, and the contact 12 is controlled to be opened when the ringer signal is not transmitted.

While the ringer signal is being sent from the working ringer device 16 to the subscriber terminal 10, the contact 12 is held in the closed state until the subscriber terminal 10 is off-hooked, so that the number of opening / closing operations of the contact 12 is reduced. When the ringer signal is not sent, the contact 12 is held in the open state, so that the ringer device 16 and the ring trip monitoring circuit 26 are separated, and the impedance of the ring trip monitoring circuit 26 is not applied as the load of the ringer device 16.

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

FIG. 2 is a block circuit diagram of an embodiment of a ringer signal transmission system according to the present invention, and FIG. 3 is a timing chart of contacts when a ringer signal is transmitted.

R and T are subscriber lines, 11 is a telephone constituting the subscriber terminal 10, 12 is a contact of the common section relay 13, 14 is a contact control circuit,
Reference numeral 16 is a ringer device which superimposes the AC signal from the ringer generator 17 on a DC voltage of -48V and sends it out. Reference numeral 18 is a sending resistor, 20 and 22 are contacts of the ringer relay 23, 24 is a power supply circuit that supplies a call current to the telephone 11, and 26 is a ring trip monitoring circuit that monitors on-hook and off-hook of the telephone 11.

The contact 12 is provided in a common part of a plurality of subscriber lines.
For example, when eight subscriber lines are mounted on one package (printed circuit board, etc.) and a plurality of such packages are provided, one contact 12 is mounted on each package, and eight contact lines are provided. It will be provided in the common part. The contacts 20 and 22 of the ringer relay 23 are provided for each subscriber line.

When a ringer signal is transmitted to a predetermined subscriber line, the contacts 20 and 22 of the subscriber line are closed to the 1 side in FIG. 2, and the contact 12 is also closed by the contact control circuit 14. As a result, the ringer signal sent from the ringer device 16 is contact 12-sending resistor 18-contact 20-subscriber line R-.
The bell circuit in the telephone set 11-subscriber line T-contact 22-flows through the path of the earth and rings the bell of the telephone set 11. Also phone
When 11 is in the off-hook state, the contacts 20 and 22 are held closed to the 0 side and the contact 12 is opened.

The contact 12 of the common section relay 13 is provided in the common section,
The operation of the contact 12 needs to take the logical sum (OR) of the contacts 20 and 22 of each subscriber line provided in the package. This can be achieved by taking the logical sum of the control signals of the ringer relays 23, but when operated in this way, the number of actuations of the contacts 12 is much greater than the number of actuations of the individual ringer relays 23. Become. For example, when the contact 12 of the common section relay 13 is provided for eight lines, the number of operations of the contact 12 is about eight times the number of operations of the contacts 20, 22 provided for each subscriber line. Therefore, in order to reduce the number of operations of the contact 12, the contact control circuit 14 is used to give the contact 12 a hysteresis (about 2 to 3 seconds) in consideration of the operation cycle of the contacts 20 and 22. As a result, the contact 12 that is transmitting the ringer signal can be kept in the closed state until the telephone 11 is off-hooked. The operation of the contacts 20, 22 and the contact 12 at this time is shown in FIG.

FIG. 4 is a block diagram of an embodiment of a contact control circuit, FIG.
The drawing shows a timing chart according to the embodiment of FIG. 4, and one embodiment of the control of the contact 12 by the contact control circuit 14 shown in FIG. 2 will be described below.

The contact control circuit 14 includes an OR circuit 28, a shift register 30, and a relay driver 32.
Are in control. A common section relay 13 is provided for eight subscriber lines from SD0 to SD7. The common part relay 13 is driven by a relay driver 32, and the ringer relay 23 is driven by a relay driver 34. When a control signal for sending a ringer signal is input to SD0, the ringer relay 23 provided in this subscriber line operates in response to the high level and low level of the control signal. At the same time, the control signal input to SD0 is input to the CLEAR terminal (CL) of the shift register 30 via the OR circuit 28. The + 5V power supply voltage is applied to the D terminal of the shift register 30,
At the R terminal entrance, the level of the control signal is inverted. As a result, when a control signal is input to SD0, the CLEAR terminal of the shift register 30 becomes low level and at the same time the outputs Q _{0 to} Q ₃ become high level. The output of Q3 ₃ during from when the control signal SD0 is changed from the high level to the low level of more than three times the clock period, and has a high level state.

Since the common relay 13 operates according to the high level and the low level of Q ₃ of the shift register 30, the contact 12 of the common relay 13 can have hysteresis.

EFFECTS OF THE INVENTION Since the ringer signal transmission system of the present invention is configured as described above in detail, the number of relays can be remarkably reduced, and the load of the ringer device when the ringer signal is not transmitted can be eliminated, resulting in unnecessary power loss. There is an effect that it is possible to prevent.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block circuit diagram of an embodiment of a ringer signal transmitting system according to the present invention, FIG. 3 is a timing chart of contacts at the time of transmitting a ringer signal, and FIG. 4 is contact control. A block diagram of an embodiment of the circuit, FIG. 5 is a timing chart according to the embodiment of FIG. 4, FIG. 6 is a block circuit diagram of a conventional ringer signal transmission system, and FIG. 7 is a contact of a relay for each subscriber line. FIG. 3 is a block circuit diagram of a ringer signal transmission system in the case of providing the. 10 …… subscriber terminal, 11 …… telephone, 12, 20, 22, 36 …… contacts, 13 …… common part relay, 14 …… contact control circuit, 16 …… ringer device, 17 …… ringer generator, 18 …… Sending resistance, 23 …… Ringer relay, 24 …… Feed circuit, 26 …… Ring trip monitoring circuit, 28 …… OR circuit, 30 …… Shift register, 32,34 …… Relay driver,

Claims (1)

[Claims] 1. A ringer signal transmission system for transmitting a ringer signal from a ringer device (16) to a plurality of subscriber terminals (10), wherein a relay contact (12) is provided at a common part of a plurality of subscriber lines, A contact control circuit (14) for controlling the operation of the contact (12) is provided, and while the ringer signal is being sent, the contact (12) provided in the common section is controlled by the contact control circuit (14) to be continuously closed. , A ringer signal transmission system characterized by controlling the contact (12) to open when the ringer signal is not transmitted.