JPS58117792A - Interface circuit for telephone exchange - Google Patents

Abstract

PURPOSE:To eliminate the need for the provision of a simultaneous start preventing circuit for an exchange at the called party, by connecting a strap to a caller when a power supply is interrupted and earthing the circuit, disconnecting the strap from the called party, and making the circuit open. CONSTITUTION:Relays 71-724 give outputs to an SR line of channels 1-24, i.e., channels CH1SR-CH24SR and they are constituted with transistors. Since a switch SW3 is set off when the power supply is applied normally, diodes D1- D24 are reverse-biased and the relays 71-724 are operated independently at each channel. Further, when the power supply is interrupted, the SW3 is set on, the diodes D1-D24 are forward-biased at the same time and each SR line of the channels CH1-CH24 is earthed. Since the SR line connected to the called party disconnects all straps 10i at a central controller when the power supply is interrupted, each SR line of the channels CH1-CH24 is opened, then no simultaneous start happens.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an interface circuit for a telephone exchange using a semiconductor switch that outputs a ground signal to the calling side exchange and an open signal to the called side in the event of a failure.

(2) Technical background In general, in a telephone communication network, as shown in Figure 1, the calling side telephone (1) consists of a switchboard (2), a terminal equipment (3), a trunk line (4), and a terminal equipment (5). ), and are connected to the desired called telephone C1l via the exchange (6). In this case, between the exchange 4m1 (2) and the terminal equipment (3) and the terminal equipment (5)
and the exchange (6), many control numbers are transmitted using the open/earth interface. For example, when a connection signal is sent to the terminal stations (3) and (5), the interface is made using a signal line called the IllC887S line, as shown in FIG. Figure 2 shows the device shown in Figure 1 (
2) (This is a partial diagram showing the trunk among the 3 trunks, and the connection signal is the SR of the exchange (2))
-8R) rank) (2a) and the signaling processing section (3a) of the terminal device (3), but from the signaling processing section (3a) to the 8R) rank (2a) is a switch 8W, The 8R signal is sent out when the switch 8W is turned on or off.Similarly, the SS signal is sent out from the SR rank (Za) to the signaling processing unit 3m when the switch 8W is turned on or off. When the switch SW is on, earth air is sent to the relay (to) to operate it. One end of the relay (2) is connected to the 143V station power supply. Similarly, when the switch SW is on, the relay (
2) K Jiqi is sent out and this is the name of the meeting. to the relay)
Also, one end of the switch sw1 is connected to the 14lVO local power supply. (3) Prior art and problems Conventionally, a mechanical switch has been used as a SW, and a normally-on type pipe that turns off when energized once is used to send out earth air when the power is cut off. Therefore, when the power is turned off, the signaling processing unit (3a), (in)
<2a) Earth air was being sent to 46m) regardless of the calling or called side. If the call is not made, the air is sent to (31) and 121).

The exchange (2) determines that the line is blocked and does not access it. However, if the called side (5a) sends air to 11, the exchange determines that it is activated.The latter condition occurs when the system AM power is cut off, so the PCM-
In the case of the 24-channel system, there was a drawback that all 24 channels were activated at the same time. For this reason, the called side exchange was equipped with a circuit to prevent simultaneous activation.
8W, there is a tendency to use switching using semiconductor devices (so-called electronic lidding), but when using electronic relays, the operation becomes open when the power is cut off, and ground air cannot be sent to the calling exchange. was there.

(5) Purpose of the Invention The purpose of the present invention is to use an electronic relay as a switch for sending out the 8R signal, and - without using a simultaneous activation prevention circuit, when a failure occurs, the calling side exchange receives an electric current, and the called side exchange receives a K is to provide an ink 7 bus circuit for a telephone exchange that can send an open signal.

(6) Configuration of the Invention The configuration of the present invention is a telephone exchange that is provided between a telephone exchange and a relay terminal equipment, and uses 8878RIII when transmitting calls via the calling/receiving MT relay line of the telephone. In this interface circuit, a semiconductor switch is used as a switch for transmitting an 8-wire signal, and the output terminal of the semiconductor switch is connected to one end of a series circuit of a strap and a diode that can be individually disconnected (tW!). The other end is connected to a switch that operates when the trunk line fails or the power is cut off to form a ground connection, and a strap is connected to the calling side in the event of a trunk line failure or power cut. Earth pipe output, called rtcF! It is to cut the strap and output an open.

(6) Embodiments of the invention Examples of the invention shown in the drawings will be described below. Ji
FIG. 13 shows a circuit diagram of an embodiment of the present invention, and describes a case in which a PCM-24Bt is used as a terminal device and a power failure occurs as a failure.The Ol system is formed with 24 channels.

Each system has its own power supply. Additionally, control is basically system independent. Therefore, for example, when the power supply is cut off, if you want to apply electricity to the S line on the calling side, a failure signal from the power panel will connect the calling side to II1. It is necessary to send out the ground air for all SR lines for all channels. #! In Figure 3 (
71) to (7!4) are channels 1 to 2408
B714, that is, CHISB to cn,, sa [output t-
Shows the connected relays, each consisting of one or more transistors (when a large current is required). The output end of the relay (71) etc. is the terminal (8t) ~ (8*4),
2) Rank (101) to (14)! 4), terminal (91
) to (914) 1') t-via diodes D1 to D
0 diode D connected to the cathode of □ separately,
The anodes of ~D24 are connected to common #ci and connected to the non-ground side contact of the switch SWs. switch 8W
s is configured to be turned on when the power is turned off.

When the 0 power supply, which is normally off, is normally supplied, the switch 8W is off, so the diodes D1 to I)x4 are turned upside down and the anodes are open, so they are reverse biased. Relay (71) ~ (
7mm) operates independently for each channel. If the power supply is cut off for some reason, the switch SWJ is turned on and the diodes D1 to D! Each of the four seven nodes is grounded. As explained in Fig. 2, the S& wire is connected to the station power supply -4l1V via the relay in the exchange (2), so when the switch SW is turned on, the diodes D, ~D14 are turned on. at the same time,
biased in the lj direction. Therefore relay (7,)
The output end of ~(7g4) is grounded via diodes D and ~D□, and the busy air is simultaneously sent to each SR line of channels CH and ~CH■. In addition, the SR line connected to the called side has all system rungs (to) disconnected by the central controller when the power is cut off, so relays (71) to (7) are disconnected.
xi) are open, channels CH1 to CH! Each Sa@ of 4 is an open output and 9 is invalid to the called exchange.
There will be no sudden start-up.

In FIG. 3, the same effect can be obtained even if the Stragg acid is provided on the switch SW side of the 7th node of the diode D. Further, even when a trunk line fault occurs, a similar operation can be performed by providing a circuit for detecting it and turning on the output switch SW, t-.

(7) Effects of the Invention As described above, according to the present invention, a transistor is used as a switch for sending an SR signal, and when a failure such as a power cut occurs, the earth is sent to the calling exchange. It is possible to send an open message to the called side exchange and restore the exchange. - There is no need to provide a special simultaneous start prevention circuit, and since it is configured to be connected to a single switch via a diode, the number of parts is small and the cost is low.

[Brief explanation of the drawing]

Figure 811 shows the configuration of the telephone communication network lIi! Figure I#, Figure 1 is an explanatory diagram of the operation of the ink 7 bus circuit between the mobile phone exchange and the terminal equipment in Figure 1, and Figure 8 is a circuit diagram showing one embodiment of the present invention. 1) - Calling subscriber, (2) - Calling exchange, (3)
- Calling side terminal equipment% (4) - Trunk line. (5)... Called side terminal equipment, (6) - called side exchange. αt... Called subscriber, (71) to (714) - Axis relay. (8□) ~ (8 layers, 4 people (9 layers) ~ (9 mm) one terminal.
2)・-Relay sw, , sw, , sw, ,-
switch. (D,) ~ (D*a) = Diode patent applicant Fujitsu Ltd.

Claims (1)

[Scope of Claims] 88 is provided between a telephone exchange and a relay terminal equipment, and when transmitting calls and calls of telephones via a trunk line.
78IL@@Used In the ink 7 circuit of the Sui telephone exchange, a semiconductor switch is used as a switch for sending out S & Confucian numbers. One end of a series circuit of a separately disconnectable front strap and a diode is connected to the output end of the semiconductor switch, and the other end is connected to a switch that operates to generate a ground connection sound when a trunk line fails or the power is cut off, An interface circuit for a telephone exchange characterized in that when a trunk line failure occurs, when the power is cut off, the calling IIK connects a strap and outputs a ground signal, and the called side Kid's strap is disconnected and an open tat is output.