JPS6056033B2 - Call path control method in button telephone equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a call path control method in a button telephone device,
In particular, it relates to a call path control method in a button telephone device configured to centralize the call path switch and its control circuit in the main device and reduce the number of core wires of the cable connecting between the main switch and the button telephone device. It is something.

Conventionally, this type of device uses a mechanical switch such as a relay, or a MOSFET as a communication path switch.
PN analog switch with electrical control gate
Semiconductor switches such as PN (Surface Lister) switches were used.

However, mechanical switches have drawbacks such as increased size and increased power consumption, and MOSFETs, which are semiconductor switches, have a large DC resistance when conducting. In addition, in the case of a PNPN switch, the control gate for driving the trigger is connected to an external power supply system such as a commercial power supply, so the PNPN switch is directly connected to the office line, which deteriorates the balance and insulation of the office line. It is necessary to take measures against noise and lightning surges.
A big practical problem arose. Therefore, in order to solve these problems, conventional methods have been used to disconnect the central office line and the communication path switch using a transformer or the like in a direct current manner, and connect only an alternating current connection. However, this method not only deteriorates call quality but also requires a power supply for supplying call current to the Mibutton telephone to be provided in the main device, which has the disadvantage of increasing the size of the power supply device. The present invention solves these drawbacks by:
A light-driven PNPN switch element is used in the communication path switch, the main unit control power source and the switch element are electrically separated, and the office line and the switch element are connected in direct current manner, and the office line generated by this connection is Disturbances such as disconnection of the PNPN switch caused by instantaneous interruption of current are solved by using a latch memory in the thyristor drive section, and the telephone set is configured so that the telephone current supply is obtained from the central office line, thereby solving the above-mentioned drawbacks. The purpose is to eliminate this problem and also provide a call retention function in the event of a power outage.

This will be explained in detail below. In the configuration of the present invention, the button telephone device includes a semiconductor switch element that directly connects the communication circuit between the office line and the button telephone in direct current or alternating current. Switching means with self-holding properties, e.g. PNPN
A switch is used, and the element has a structure in which the communication signal path and the control signal input section (gate) are electrically separated, and the gate is connected to a flip-flop circuit, for example. In other words, the communication path is continuously driven by the latch means, so that the communication path has a dual function of holding the communication path by the PNPN switch and the latch means. This system is particularly effective when program control such as a microcomputer (MPU) is used as the control means for the button telephone device. In other words, during the network control stage of a station, such as when making a dial call on a button telephone or operating a line key, there are many phenomena in which the direct current applied to the line is momentarily cut off during line control, and each time this happens, the call path switch is disconnected. The microcomputer is required to carry out a processing operation to follow it, which increases the burden on the microcomputer and may cause problems such as boundary line disconnections due to processing delays. As mentioned above, this problem cannot be avoided by using a switch element with a self-holding function and directly connecting to the central line, and the present invention solves this problem by using the double holding mechanism.

Specifically, the self-holding function of a PNPN semiconductor element (thyristor) is used as the first memory means, and the gate drive memory is used as the second memory, so that the first memory is used during normal calls. When the second memory is disconnected, the second memory operates to reconnect the switch, and when the second memory stores 1, the switch can be kept connected.

A detailed explanation will be given below using a specific circuit example. FIG. 1 shows an embodiment of a button telephone device using the present invention.

In Fig. 1, ME is the main device, KTl, KT2,...
..., KTn is a button telephone, 1 is a microprocessor, 2 is RAM (raw dumb access memory),
3 is ROM (read only memory), 4 and 5 are office line circuits, and 6 is communication path cross point switch (thyristor).
, 7 is a communication path switch driving memory circuit (the second memory), 8, 9, . . . , 10 is an I/0 boat, 11
~16, 22, 23, 32, 33, 42, 43 are inverters, 21, 31, 41 are telephone communication circuits, 24, 3
4, 44 are telephone control circuits, 25, 35, 45 are indicators such as lamps, 26, 36, 46 are data input means such as telephone keys, 27, 37, 47 are telephone lines, and 28, 38, 48 are controls. Line 17 represents a bus line. Next, as the operation, the operation between the key telephone KT and the main device (2) will be explained.

First, when you operate the telephone key 26 of the telephone KTl, the parallel
It is converted into a time-division pulse signal by the control circuit 24 of the telephone that performs serial change, and its output is applied to the I/O boat 8 via the inverter 22, cable 28, and inverter 11, and under the control of the microprocessor 1, RAI!
12 is stored.

This stored content is controlled by the microprocessor according to the program memory in ROM 3, and is then used as information to light up an indicator (for example, a station line lamp) on the I/0 board 8.
, is input to the telephone control circuit 24 through the inverter 12, cable 28, and inverter 23, and is processed there;
The display 25 is operated (lit). At the same time, a signal that activates (lights up) the display of other telephones KT (KT2...KT.) is transmitted from the I/O assigned to each KT.
Transmitted through boats, inverters and cables. This causes the display to operate, allowing it to be known that the line (for example, a central office line) is being used in another KT. On the other hand, the contents of the telephone key 26 stored in the RAM are further processed by the program contents of the ROM 3, and the communication path switch drive memory circuit (the second memory) 7 is operated, and the output thereof is used for the communication path cross point switch 6. and connect the office line (for example, office line 1) to the telephone call circuit 2 of the telephone KTl.
1 to enable communication between central office line 1 and telephone KTl. Next, FIG. 2 shows an embodiment showing a part of the communication path cross-point switch 6. As shown in FIG.

In FIG. 2, 21 is a communication circuit of the telephone KTl shown in FIG. 1, 51 is an optically coupled PNPN (thyristor) switch element, 54 is a flip-flop circuit (part of the second memory 7), and 52 is a relay. The contact 53 represents a diode bridge circuit.

In FIG. 2, when the element 51 is disconnected, the voltage (
Generally, approximately 48 µDC) is applied. Here, when the flip-flop circuit 54 is set, its output causes the gate 51 of the optically coupled thyristor switch element 51 to
-1, and its thyristor switch element 51-2,
51-3 is turned on. As a result, the station line current flows through the diode bridge 53, the relay contact 52, the thyristor switch 51-3, the telephone communication circuit 21, the thyristor switch 51-2, the relay contact 52, and the diode bridge 53. The central office line forms a loop and enables the telephone's telephone communication circuit 21 to make and answer calls and make telephone calls. Next, when the thyristor switch 51 is to be disconnected at the end of a call, etc., the flip-flop 54 is reset, and then the relay contact 52 is instantaneously broken to extinguish the thyristor switch 51. Although the flip-flop 54 is in the set state, even if the thyristor switches 51-2 and 51-3 are turned off due to a momentary interruption of the station line current, the drive current will not flow through the gate circuit 51-1. Therefore, 51-2 and 51-3 are re-ignited and restored to the on state. The above operation can prevent the thyristor switch from turning off when the station line current is momentarily interrupted.

Figure 3 omits the diode bridge circuit in Figure 2,
Another embodiment will be shown in which the thyristor switch 55 has a bridge configuration as shown in the figure and performs the switch function and the voltage rectification function at the same time.

In the case of the connection shown in FIG. 3, the DC voltage drop is reduced compared to that of FIG. 2, and the communication quality is improved. It goes without saying that in FIGS. 2 and 3, a pulse generating circuit can be used in place of the flip-flop 54 to perform pulse driving in contrast to the DC driving shown in FIGS. 2 and 3.

Furthermore, a microcomputer can also be used as the control circuit 24 of the telephone. As explained above,
According to the present invention, it is possible to put into practical use a central button telephone device that is directly connected to the central office line and supplies communication current from the central office line, and is small, high in quality, low in price, and low in power consumption. A telephone device for consumption can be provided.

Furthermore, the practical effects are extremely large, such as eliminating the need for battery backup to prevent calls from being cut off in the event of a power outage, which was a disadvantage of the centralized key telephone system.

[Brief explanation of drawings]

FIG. 1 shows one embodiment of the button telephone device according to the present invention;
The figure shows one embodiment of the communication path switch circuit of the present invention, and FIG. 3 shows another embodiment of the communication path switch circuit of the invention. In the figure, dumb is the main device, KTl, KT2, ... are key telephones, 1 is a microprocessor, 2 is RAMl3
ROM 16 is a communication path cross point switch, 7 is a communication path switch drive memory circuit, 21, 31, 41 are telephone communication circuits, 34, 34, 44 are telephone control circuits,
25, 35, and 45 are indicators; 26, 36, and 46 are data input means; 51 is an optically coupled PNPN element; and 52 is a relay contact.

Claims (1)

[Claims] 1. In a button telephone device using a thyristor element as a communication path switch, the main device includes an optically coupled drive type PNPN.
A first switch means for switching the communication path constituted by a semiconductor element, a second switch means for extinguishing the switch, and an ignition current continuously applied to the control signal input terminal of the first switch means. and a first control means for controlling the memory means, an operation means, a display means, and a second control means for controlling them are provided in the telephone, and the above-mentioned A signal corresponding to the operating means is input by the operating means to the first controlling means via the second controlling means, and the memory means is set by the output of the first controlling means. 1
The switch means is held in the on state by optical coupling drive to enable communication with the central office line, the memory means is reset, the second switch means is driven, and the first switch means is driven. 1. A call path control method in a button telephone device, characterized in that the button telephone device is configured to extinguish the arc.