JPS63122353A - Line control unit circuit - Google Patents

Abstract

PURPOSE:To remarkably decrease the cost by providing a switch switching a telephone set and a connection device so as to select talking and data communication and coupling the switch and the connection device via a DC circuit and a communication transformer thereby simplifying the circuit constitution and decreasing number of relays. CONSTITUTION:A switch 23 is a switch to change over a telephone set 21 and a Captain receiver 22, a call collision prevention circuit 25 and the telephone set 21 are connected to the normally closed contact, and the Captain receiver 22 is connected to the normally open contact via a DG circuit 26, a communication transformer 27 and a changeover relay 28. When it is confirmed by other circuit that the telephone set 21 is not in use at present, the switch 23 is changed over to the position of the normally open contact. In inputting a pulse dial mode signal from an input terminal 341, a shunt contact 33 of the DC circuit 26 is closed to short-circuit the primary side of the communication transformer 27. In this state, when a pulse signal is inputted from an input terminal 36, the switching section 32 is turned on/off synchronously with the dial signal and the pulse signal is sent via a telephone line. Finally, the shunt contact is opened and communication or line is monitored.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention is directed to an LCU (LCU) for controlling switching between a normal telephone and analog telephone connection equipment such as a captain to a telephone line.
(line control unit) circuit.

``Prior Art'' As shown in FIG. 4, a conventional LCU circuit connects a captain receiver (1), which is an analog telephone connection device, to a telephone line (
2) DC circuit (3) when connected to (2) for communication
and a DC circuit (4) when dialing for captain are provided separately, and when dialing for captain, relay (5) is provided separately.
) to the normally open contact side, and connect the dial pulse sending circuit (
A dial signal was sent from 6) to the telephone line (2) (2), and then the relay (7) (7) was switched to the normally closed contact side in order to connect to the DC circuit (3) for 1 communication. In addition,
In FIG. 4, (8) is a telephone, (9) is an electronic computer, (10) is a level conversion circuit, (11) is a dial pulse sending control circuit, and (15) is a modem (modulation/demodulation device).

[Problem to be solved by the invention] Conventionally, when the captain communicated, the dialing DC circuit and the communicating DC circuit were separately provided.
This has the problem of not only increasing the number of parts but also requiring a large number of highly reliable relays, resulting in an overall high cost.

``Means for Solving the Problems'' The present invention was made to solve the above-mentioned problems, and it uses a converter to switch between the telephone set and the connected equipment on the telephone line, thereby switching between calls and data communication. In a device configured to perform selective dialing, the converter and the connected device are coupled via a DC circuit and a communication transformer, and the DC circuit includes a switching unit that sends out a pulse dial signal;
1 of the communication transformer during this pulse dial mode.
This device is equipped with a shunt contact portion that short-circuits the next side, and a line resistance that increases the line resistance of the DC circuit in the pulse dial to a predetermined value or more.

"Operation" After confirming through other circuits that the telephone is not currently in use, the converter is switched to the connected device side. Next, when the pulse dial mode signal is input, the shunt contact portion of the DC circuit closes to short-circuit the primary side of the communication transformer. When a pulse dial signal is input in this state, the switching section turns on and off in synchronization with the dial signal, and the pulse signal is sent out via the telephone line. Finally, turn off the shunt contacts and monitor the communication or line.

"Example" Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Figure 1, (20) (20) is a telephone line, (2
1) is a telephone, (22) is a captain receiver as an analog telephone line connection device, and (23) is a telephone (2).
1) and the captain receiver (22).

A hook switch (24) consisting of a photocoupler is connected to the normally closed contact side of this conversion II (23), and sends a hook-off signal to the calling collision prevention circuit (25) to prohibit calling from other devices. .

A DC circuit (26) is connected to the normally closed contact side of the converter (23).
.

It is coupled to the modem (29) of the captain receiver (22) and the tone dial sending and line monitoring circuit (30) via a communication transformer (27) and a switching relay (28). The DC circuit (26) includes a diode (31) for keeping the polarity constant, a switching section (32) for sending out a pulse dial signal, and a shunt contact section (33) that short-circuits the primary side of the communication transformer (27). , is provided with a line resistor (34) that makes the line resistance equal to or higher than a predetermined value (50Ω). The pulse dial signal sending switching unit (32) also connects a first photocoupler (3) coupled to a pulse signal input terminal (36) from the CPU (35).
7).

A second transistor (38) that turns off and turns on when this photocoupler (37) turns on and off, a first transistor (39) that turns on and turns off when this second transistor (38) turns on and off, and an excessive voltage. from the first photocoupler (3
7), a Zener diode (40) that protects the circuit, and a bypass capacitor (41) that prevents the DC circuit (26) from abnormally oscillating when the line DC voltage temporarily falls below the threshold of the down diode (31). It is composed of etc. The shunt contact portion (33) includes a transistor (42) coupled to a mode signal input terminal (41) that outputs an H signal during communication and an L signal during dialing, and a transistor (42) that is activated when this transistor (42) is turned off. The photocoupler (43) includes a second photocoupler (43), a third transistor (44) that is turned on when the second photocoupler (43) is activated, and the like.

The operation of the above configuration will be explained 6. First, after confirming with other circuits that the telephone (21) is not currently in use, the converter (23) is switched to the normally closed contact side.

Here, when transmitting the pulse dial of the captain receiver (22), an L signal is output from the mode signal input terminal (41). Then, the transistor (42) turns off,
The second photocoupler (43) is activated, and the third transistor (44) is turned on to short-circuit the primary side of the communication transformer (27). At this time, the electrical conditions of the DC circuit are satisfied by inserting the line resistor (34).

Next, when a pulse dial signal is input from the pulse signal input terminal (36), the first photocoupler (37) is turned on and off, and the second transistor (38) is turned on and off accordingly.
and the first transistor (39) is turned off and on. For this reason, from the converter (23) to the telephone line (20) (20)
A pulse dial signal is sent to the

Next, when communicating or monitoring the line using the captain receiver (22), set the mode signal input terminal (41) to H.
to turn off the third transistor (44), and set the pulse signal input terminal (36) to L to turn off the first and second transistors.
The transistors (39) and (38) are turned on and the telephone line (
20) Input the data from (20) into the modem (29).

To perform tone dialing, the switching relay (28) is switched to the tone dial sending and line monitor circuit (30) side to send out a DTMF signal.

In the embodiment described above, a switching relay (28) was provided between the communication transformer (27) and the captain receiver (22), but
However, as shown in FIG. 2, the middle point of the secondary side of the communication transformer (27) is grounded, and one end is used as a tone dial and line monitor terminal (45).
The other end can be used as a modem terminal (46).Also, as shown in FIG.
48) Tone dial terminal (SO) via (49)
It may be used as a single-line monitor terminal (51) or a modem terminal (52).

"Effects of the Invention" Since the present invention is configured as described above, the circuit configuration is simplified and the number of relays can be reduced, resulting in a significant cost reduction. Further, it has the advantage that it is easy to monitor the line after pulse dialing.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing one embodiment of an LCU circuit according to the present invention, and FIG. 2 is an electric circuit diagram showing a first example in which a switching relay on the secondary side of a communication transformer is omitted. FIG. 3 is an electric circuit diagram showing the second example, and FIG. 4 is a block diagram of a conventional LCU circuit. (20)...Telephone line, (21)...Telephone, (2
2)...Connection device (captain receiver), (23)
...Converter, (24) ...Hook switch, (2
6)...DC circuit, (27)...communication transformer,
(29)...Modem, (30)...Tone dial sending and line monitoring circuit, (32)...Switching unit for sending pulse dial signal, (33)...Shunt contact unit. (34)...Line resistance, (36)...Pulse signal input terminal. (37)...First photocoupler, (38)...Second transistor, (39)...First transistor, (41)...Mode signal input terminal, (43)...・
Second photocoupler, (44)...Third transistor.

Claims (3)

[Claims] (1) In a device in which a telephone line is switched between a telephone set and a connected device using a converter to selectively perform calls and data communication, a DC circuit and a communication circuit are connected between the converter and the connected device. The DC circuit is coupled to the transformer, and includes a switching unit that sends out a pulse dial signal, a shunt contact unit that shorts the primary side of the communication transformer during the pulse dial mode, and a DC circuit in the pulse dial. 1. A line control unit circuit comprising: a line resistance for making the line resistance equal to or higher than a predetermined value. (2) The switching unit that sends out the pulse dial signal includes a photocoupler that turns on and off in response to the pulse dial signal.
The line control unit circuit according to claim 1, comprising a transistor that opens and closes a DC circuit in response to turning on and off of this photocoupler. (3) The shunt contact portion consists of a photocoupler that operates in the pulse dial transmission mode, and a transistor that controls short-circuiting on the primary side of the communication transformer in response to turning on and off of the photocoupler. The line control unit circuit according to item 1 or 2.