JPH0223062B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention provides a telephone using a semiconductor switch that outputs an open signal from a relay terminal device to an originating telephone exchange and an open signal to an incoming telephone exchange in the event of a failure. It relates to an interface circuit of a switch.

(2) Background of the technology In general, in a telephone communication network, as shown in FIG. It is connected to the side telephone 11. In this case, between the exchange 2 and the terminal equipment 3 and between the terminal equipment 5 and the exchange 6
In between, many control signals are transmitted in SS-SR signaling using an open/ground-air interface. This SS-SR signaling system is also called the E&M system, and transmits and receives signals independently. For example, when interfacing connection signals at terminal stations 3 and 5, as shown in Figure 1,
Interface with a signal line called the SS-SR line. FIG. 2 is a diagram partially showing the trunks in the devices 2 and 3 in FIG. 1, and the connection signal is the SR trunk (or SS/SR trunk) 2a of the exchange 2
The SR signal is transmitted and received between the signal processing unit 3a and the signaling unit 3a of the terminal device 3, and the SR signal is sent from the signaling processing unit 3a to the SR trunk 2a by turning on or off the switch _SW1 . Similarly, an SS signal is sent from the SR trunk 2a to the signaling processing section 3a by turning on or off the switch _SW2 . When switch SW ₁ is on, earth air is sent to relay 15 to operate it. relay 15
One end is connected to the -48V station power supply. Similarly, when switch SW ₂ is on, relay 1
Jiqi is sent to 6 to operate it. One end of the relay 16 is also connected to the -48V station power supply.

(3) Conventional technology and problems Mechanical switches have traditionally been used as switches SW ₁ and SW ₂ , and normally-on type switches that turn off when electricity is applied are used to send out earth air when the power is turned off. Therefore, when the power is turned off, the signaling processing units 3a and 5a are
Earth air was being sent to a and 6a. If transmission is not activated from the originating SR trunk 2a and the air is sent from 3a to 2a,
Exchange 2 determines that the line is blocked and does not access it. However, when the receiving side 5a sends out air to 6a, the exchange 6 determines that the call is activated. Since the latter state occurs when the system is powered off, the PCM-24 system had the disadvantage that all 24 channels were activated at the same time. For this reason, the terminating exchange 6 was equipped with a circuit to prevent simultaneous activation.

In recent years, the aim has been to achieve smaller size, higher reliability, and lower price.
There is a tendency to use semiconductor element switches (so-called electronic relays) as SW ₁ and SW ₂ , and if electronic relays are used, they will open when the power is turned off, and earth air cannot be sent to the originating exchange. There was a drawback.

(4) Purpose of the Invention The purpose of the present invention is to use an electronic relay as a switch for sending out SR signals, without using a circuit to prevent simultaneous activation, and to enable the transmitting exchange to receive ground air,
The object of the present invention is to provide an interface circuit of a telephone exchange capable of sending an open signal to a destination exchange.

(5) Structure of the Invention The structure of the present invention is provided between the telephone exchange and the relay terminal equipment, and receives control signals such as activation and dialing from the originating telephone, and responses such as response and call termination from the terminating telephone. In the interface circuit of a telephone exchange that uses SS-SR lines when transmitting control signals via trunk lines, an SR signal is provided for each trunk line that is transmitted from the relay terminal equipment to the originating and terminating telephone exchanges. In parallel with the sending relay circuit, a switch is provided in which one end of a series circuit of a strap and a diode that can be individually disconnected from each trunk line is connected in common. The strap is connected to the originating telephone exchange to form a ground connection, and the strap is disconnected to the terminating telephone exchange to prevent trunk faults. or when the power is cut off, an open signal is output to the outgoing telephone exchange and an open signal is output to the incoming telephone exchange.

(6) Embodiments of the invention Examples of the invention shown in the drawings will be described below. FIG. 3 shows a circuit diagram of an embodiment of the present invention,
A case will be described in which a PCM-24B is used as a terminal device and the failure is a power outage or a trunk line failure. One system is formed with 24 channels, and each system has its own power supply. Additionally, control is basically system independent. Therefore, for example, when the power is cut off, when applying earth air to the SR line on the transmitting side, it is necessary to send earth air to all SR lines for all channels connected to the transmitting side in response to a fault signal from the power panel. In Fig. 3, 7 ₁ to 7 ₂₄ indicate relays that connect outputs to the SR lines of channels 1 to 24, that is, CH ₁ SR to CH ₂₄ SR, each of which has one or more transistors (when a large current is required). It consists of The output terminals of relay 7 ₁ etc. are terminals 8 ₁ to 8.
₂₄ , strap terminals 10 ₁ to 10 ₂₄ , terminals 9 ₁ to 9
₂₄ to the cathodes of diodes D ₁ -D ₂₄ respectively. Diode D ₁ ~ _{D 24}
The anodes of each are connected in common and the switch
Connected to the non-ground contact of SW ₃ . switch
SW ₃ is configured to be turned on (shown by the solid line in FIG. 3) when the power is turned off, and turned off (shown by the dotted line in FIG. 3) under normal conditions. When power is supplied normally, switch SW ₃
Since all of the diodes D ₁ to _{D 24} have their anodes open, they are reverse biased, and the relays 7 ₁ to 7 ₂₄ operate independently for each channel. If the power supply is cut off for some reason, relays 7 ₁ to 7
₂₄ becomes an open output, switch SW ₃ is turned on, and the anodes of diodes D ₁ to D ₂₄ are respectively grounded. As explained in Fig. 2, the SR line is connected to the central office power supply via the relay in the exchange 2.
Since they are connected to 48V, the diodes _D1 to _D24 are simultaneously forward biased by turning on the switch _SW3 . Therefore relay 7
The output terminals of channels _CH1 to _CH24 are grounded via diodes _D1 to _D24 , and earth air is simultaneously sent to each SR line of channels _CH1 to _CH24 through strap wires. In addition, when the power to the SR line connected to the receiving side is cut off, the strap 10 is disconnected, so the relays 7 ₁ to 7 ₂₄ are opened, and at the same time each SR line of channels CH ₁ to _{CH 24} is switched to SW ₃ The ground air cannot be sent out, resulting in an open output, which will not cause an invalid simultaneous activation of the receiving exchange.

Incidentally, in FIG. 3, the same effect can be obtained even if the strap wire 10 is provided on the switch SW ₃ side of the anode of the diode D.

The strap wires 10 ₁ to _{10 24} are designed to allow the 24 channels to freely use the control of the originating and receiving side, and to ensure that the strap can send and non-send earth air even if the power is cut off. , is a strap terminal type, and the strap terminal of the channel used on the transmitting side is a strap terminal or a strap wire (8 ₁ - 9 ₁ ) to (8 _{24 )} .
-9 ₂₄ ). Furthermore, the strap terminal of the channel used on the receiving side shall be left unconnected or the strap wire shall be unwired manually by the maintenance personnel.

(7) Effects of the Invention As described above, according to the present invention, the switch is configured using a switch connected in parallel with a relay circuit for sending an SR signal, and when a failure such as a power cut occurs, the switch is connected to the originating exchange. If so, it is possible to send a ground air to block it, and send an open signal to the destination exchange to restore the exchange. There is no need to provide a special simultaneous activation prevention circuit, and since the switch is composed of a single switch, the number of parts is small and the cost is low.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the configuration of a telephone communication network, Fig. 2 is an explanatory diagram of the operation of the interface circuit between the telephone exchange and the terminal equipment in Fig. 1, and Fig. 3 is a circuit diagram showing an embodiment of the present invention. It is. 1... Originating telephone subscriber, 2... Originating telephone exchange,
3... Calling side terminal equipment, 4... Trunk line, 5... Calling side terminal equipment, 6... Calling side telephone exchange, 11... Calling telephone subscriber, 7 ₁ - 7 ₂₄ ... Relay, 8 ₁ - 8 ₂₄ , 9 ₁ to 9
₂₄ ...Terminal, 10 ₁ to 10 ₂₄ ...Strap, 15,1
6...Relay, SW ₁ , SW ₂ , SW ₃ ...Switch, D ₁
~ _D24 ...diode.

Claims (1)

[Scope of Claims] 1. A relay line that is provided between a telephone exchange and a relay terminal equipment, and transmits control signals such as activation and dialing from a calling telephone and control signals such as response and call termination from a terminating telephone. When transmitting via SS−
In the interface circuit of a telephone exchange that uses SR lines, an SR signal transmission relay circuit is installed for each trunk line in parallel with the SR signal sending relay circuit provided for each trunk line that transmits from the relay terminal equipment to the originating and terminating telephone exchange. It is equipped with a switch SW ₃ which connects one end of a series circuit of separately disconnectable straps and diodes in common, and the switch is connected so as to operate in the event of a trunk line failure or power failure to form a ground connection. The strap is connected to the outgoing telephone exchange side, and the strap is disconnected to the incoming telephone exchange side, so that in the event of a trunk line failure or power outage, the strap is connected to the outgoing telephone exchange side. An interface circuit for a telephone exchange, characterized in that it outputs an open signal to the incoming telephone exchange side, and outputs an open signal to the incoming telephone exchange side.