JP2538557B2 - Telephone terminal extension unit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a terminal expansion unit used in a telephone device, for example, a key telephone device.

[Technical Background of the Invention] Generally, as shown in FIG. 4, a key telephone apparatus includes a main unit 1 connected to a central office line and a terminal connecting section 2 of the main unit 1.
And a plurality of button telephones 4 connected via a cable 3 each having a pair of control signal line and voice signal line.

[Problems of Background Art] However, since only one button telephone can be connected to the connection terminal of one button telephone in the terminal connecting section 2 of the above-described conventional button telephone apparatus, the terminal connecting section 2 If you want to connect more telephone terminals such as telephones and intercoms than the number of telephones that can be connected to the main device 1, it is necessary to change the main device 1 to one with a large number of connectable terminals.
There was a problem that the entire system became expensive.

[Object of the Invention] It is an object of the present invention to eliminate the above-mentioned problems and to provide a terminal expansion unit which is inexpensive and can connect more call terminals than the number of connectable terminals.

[Summary of the Invention] In order to achieve the above-mentioned object, the present invention is connected to at least one office line and through a plurality of extension terminals each formed of a control signal terminal and a voice signal terminal formed in a terminal connection portion. Are connected to a plurality of extension terminals, and are connected to a specific extension terminal of a telephone device having a main device for performing switching connection between the office line and the extension terminal and between the extension terminals, and to the specific extension terminal. In a terminal expansion unit of a telephone device capable of connecting a plurality of call terminals, a plurality of terminal connection terminals for connecting the plurality of call terminals, and a plurality of the plurality of terminal connection terminals connected to the plurality of terminal connection terminals An off-hook detection circuit for detecting an off-hook state of each of the call terminals; and one of the plurality of call terminals connected to the plurality of terminal connection terminals, A changeover switch for selectively connecting to a voice signal terminal of a wire terminal, and a detection signal of the off-hook detection circuit is transferred to the main device through a control signal terminal of the specific extension terminal of the terminal connection unit, and the detection signal is transferred. In response to the instruction output from the main unit through the control signal terminal, the changeover switch is controlled to be switched, and when the main unit calls the main unit, the main unit switches the specific extension terminal of the terminal connection unit. Between the call terminal of one of the plurality of call terminals and the voice signal terminal of the specific extension terminal of the terminal connection unit by controlling the changeover switch according to an instruction output through the control signal terminal. And a control means for forming a communication path.

[Embodiment of the Invention] FIG. 1 is a block diagram showing an embodiment of a button telephone device provided with a terminal expansion unit according to the present invention, in which a control signal is supplied to a terminal connecting portion 2 of a main device 1 of the button telephone device. A plurality of extension terminals including a terminal and an audio signal terminal are provided, and a control signal terminal and an audio signal terminal of a specific extension terminal of the plurality of extension terminals are provided with a pair of control signal line and audio signal line, respectively. The terminal expansion unit 5 is connected via the cable 3-1 and the cooule 3-2
The key telephone 4 is directly connected via. Then, in the terminal extension unit 5, three extension call terminals (telephones, doorphones, etc.) 7-via cables 6-1 to 6-3 each consisting of only one pair of audio signal lines.
1 to 7-3 are connected.

Among them, the terminal expansion unit 5 includes a terminal for connecting to the control signal terminal and the audio signal terminal of the terminal connection unit 2 of the main device 1 through the cable 3-1 and three extension call terminals 7-1 to 7-7.
-Off detecting circuit for detecting off-hook of the call terminals 7-1 to 7-3 connected to the terminal connecting terminal 11, a ringing tone generating circuit 12 for generating a ringing tone signal, and a call terminal 7 connected to the terminal connecting terminal.
Changeover switch 13 for selectively changing and connecting one of -1 to 7-3 to the audio signal terminal of the terminal connection section 2 of the main device 1.
And the detection signal of the off-hook detection circuit 11 to the cable 3-1.
Is transferred to the main unit 1 through the control signal terminal of the main unit 1, and the changeover switch 13 is switched and controlled in accordance with an instruction from the main unit 1 in response to the off-hook detection signal, and a ringing tone signal is output from the voice signal terminal of the cable 3-1 to the main unit. 1 and then the cable 3 for the call from the main unit 1.
A control circuit 14 for forming a communication path with a call terminal instructed through a control signal terminal -1 by switching control of a changeover switch 13; and a power supply circuit 15 for extension call terminals 7-1 to 7-3. It consists of

On the other hand, the main unit 1 has a control circuit 21 for exchanging control signals with the key telephone 4 or expansion unit 5 connected to the terminal connection unit 2 and for controlling the communication path, and a cross point unit 22 for switching connection of the communication path. It has and.

FIG. 2 shows the key telephone 4 to the extension call terminal 7-1.
6 is a flowchart showing an incoming call operation of the expansion unit 5 when there is a call to the telephone, when the dial number of the call terminal 7-1 is transmitted from the key telephone 4 (step 10).
0), the control circuit 21 of the main device 1 reads this dial number (step 101). As a result, when it is found that the call terminal having the dial number is under the jurisdiction of the extension unit 5, the call terminals 7-1 to 7-3 under the jurisdiction of the extension unit 5 are provided.
Check whether all are empty (step 102),
If all are empty, the control circuit 21 controls the fork point unit 22 so that a call path between the call terminal 7-1 and the key telephone 4 is formed, and at the same time, the extension unit through the control signal line of the cable 3-1. The control circuit 14 in 5 is instructed to switch the changeover switch (steps 104, 10).
Five).

As a result, a call path between the key telephone 4 and the call terminal 7-1 is formed through the voice signal line of the cable 3-1 and mutual call is possible.

In this case, the control circuit 21 of the main unit 1 performs the same control even when calling from the central line, and forms a communication path with the communication terminal under the control of the expansion unit 5. The call terminals 7-1 to 7-1
If even one of 7-3 is busy, a busy tone is transmitted to the telephone 4 (step 103).

FIG. 3 shows the extension telephone terminal 7-1 to the key telephone 4.
6 is a flowchart showing the operation when a call is made to the telephone. When the call terminal 7-1 goes off-hook (step 110), this is detected by the off-hook detection circuit 11 (step 111). Then, the control circuit 14 transmits an off-hook detection signal to the control circuit 21 in the main device 1 through the control signal line of the cable 3-1 (step 112). Then, in response to the off-hook detection signal, the control circuit 21 checks whether or not all the remaining communication terminals 7-2 to 7-3 are in the idle state (step 113), and any one of them is in the busy state. If so, the off-hook of the call terminal 7-1 is invalidated (step 114). However, if the call terminals 7-2 to 7-3 are idle, the call terminal 7-1 having the off-hook
The control circuit 14 in the expansion unit 5 is instructed through the control signal line of the cable 3-1 so as to form a communication path with the key telephone 4 and the changeover switch 13 is changed over (step 115). Next, the control circuit 21 instructs the control circuit 14 to generate the ringing tone signal from the ringing tone generating circuit 12, and then controls the fork point unit 22 to transmit the ringing tone signal to the key telephone 4 ( Steps 116-1
18).

As a result, a ringing tone is generated on the telephone 4,
Waiting for response by off-hook (steps 119 to 12)
0).

Therefore, according to the above configuration, one cable 3-1
Since it becomes possible to connect a plurality of call terminals to, it is possible to add a call terminal extremely economically.

Although the ringing tone generating circuit 12 is provided in the expansion unit 5 in the above embodiment, the ringing tone generating circuit 12 is described.
May be provided in the main device 1 to cause the main device 1 to generate a ringing tone. Further, the present invention can be similarly applied to a private branch exchange.

[Effects of the Invention] As is clear from the above description, according to the present invention, a plurality of telephone terminals can be selectively connected to the terminal connection portion of the exchange, and thus the terminal of the exchange has a low-cost configuration. It is possible to install call terminals that exceed the number of connections. Therefore,
If applied to a small-scale telephone system, there is an advantage that the financial burden on the user is reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a key telephone device to which the present invention is applied, FIG. 2 is a flowchart showing an incoming call operation when an extension call terminal is called, and FIG. 3 is an extension call. FIG. 4 is a flowchart showing the operation when a call is made from a terminal, and FIG. 4 is a diagram showing the general configuration of a conventional button telephone device. 1 ... Main device, 2 ... Terminal connection part, 3-1,3-2,6-1
6-n ... Cable, 4 ... Button telephone, 5 ... Expansion unit, 7-1 to 7-n ... Call terminal, 11 ... Off-hook detection circuit, 12 ... Ring tone generation circuit, 13 ... Switching Switch, 14 ... Control circuit, 15 ... Power supply circuit.

Claims (1)

(57) [Claims] 1. A plurality of extension terminals are connected to at least one station line, and are connected via a plurality of extension terminals each formed of a control signal terminal and a voice signal terminal formed in a terminal connection portion, It is possible to connect to a specific extension terminal of a telephone device having a main device for switching connection between a station line and the extension terminal and between the extension terminals, and to connect a plurality of call terminals to the specific extension terminal. In the terminal expansion unit of the telephone device, a plurality of terminal connection terminals for connecting the plurality of call terminals and an off-hook state of each of the plurality of call terminals connected to the plurality of terminal connection terminals are detected. An off-hook detection circuit and one of the plurality of call terminals connected to the plurality of terminal connection terminals are selectively switched to an audio signal terminal of the specific extension terminal of the terminal connection unit. And the change-over switch to connect,
An instruction to transfer the detection signal of the off-hook detection circuit to the main device through the control signal terminal of the specific extension terminal of the terminal connection unit, and to output from the main device through the control signal terminal in response to the detection signal. According to an instruction output from the main device through the control signal terminal of the specific extension terminal of the terminal connection portion when calling from the main device. Thus, the telephone is provided with a control means for forming a communication path between one communication terminal of the plurality of communication terminals and a voice signal terminal of the specific extension terminal of the terminal connection unit. Device terminal expansion unit.