JPH0636528B2 - Telephone switching equipment - Google Patents

Description

The present invention relates to a telephone exchange apparatus having a voice calling function (paging function).

"Prior Art" In a telephone switching device that accommodates a large number of extension telephones so that at least the extension telephones can be selectively connected to each other, as a call display function of a called extension telephone, a voice call is made by a calling extension telephone. The function is known. In order to realize this function, conventionally, a data bus other than a communication line is required between the exchange and the extension telephone, and the data bus supplies electric power to a control circuit of the telephone and transmits a control signal. Therefore, there has been a drawback that wiring of four lines is required between the exchange and the extension telephone, and the circuit configuration of the extension telephone becomes complicated.

Therefore, proposals for improving these have been made, and are described in, for example, JP-A-52-79710. Further, Japanese Patent Application Laid-Open No. 52-92408 discloses a system in which a calling signal from an exchange is prevented from flowing from a speaker.

However, in all of these proposals, an amplifier as a loudspeaker is provided on the exchange side.

In recent years, switching devices have become electronic, and since switching switches and the like are also made of semiconductors, a high-power signal cannot be applied to a communication path. Therefore, it is necessary to provide an amplifier for voice call on the telephone side. Therefore, each of the above proposals has a problem in that it cannot be directly used for an electronic telephone exchange device.

That is, in order to realize the paging function in the electronic telephone exchange apparatus in which the amplifier must be provided on the telephone side, conventionally, 4-wire wiring is required.

[Problems to be Solved by the Invention] The present invention can realize a paging function by two-wire wiring between a telephone exchange and an extension telephone even in a telephone exchange apparatus in which a communication path switch is electronic, and has a circuit configuration of the extension telephone. The aim is to obtain an inexpensive telephone exchange that does not become complicated.

[Means for Solving the Problems] Therefore, the present invention provides a telephone switching apparatus that accommodates a large number of extension telephones and enables selective connection between extension telephones at least. A loudspeaker that amplifies a voice signal given to a speech path by an amplifier serving as an operating power source, the loudspeaker, a high impedance circuit connected to the power feeding path of the amplifier, and the loudspeaker is turned on depending on the polarity of the speech path. A control means for controlling the OFF state is provided, and a loop resistance detection circuit for detecting a loop resistance of the extension telephone and a levers circuit for inverting the polarity of the communication path are provided in the extension circuit of the exchange, and the levers circuit is an extension telephone. Is driven by the output result of the loop resistance detection circuit when calling.

[Embodiment] FIG. 1 is a block diagram of a telephone exchange apparatus embodying the present invention, in which portions not directly related to the present invention are omitted. In the figure, 1 is an exchange, 2 is an extension telephone, 4 is an extension circuit, 3 is a communication path, 3a, 3b and 3c, 3d are connection terminals thereof, and an extension circuit 4 of the exchange 1 and a connection terminal 3 are provided.
Although a and 3b are provided in a large number corresponding to the number of extension telephones to be connected, they are shown as representatives. Reference numeral 5 denotes a loop resistance detection circuit, which is configured to detect a change in the resistance value between the terminals 3c and 3d of the extension telephone 2 and send an output, and 5a is its output line. Reference numeral 6 is a power supply circuit for supplying power to the loop resistance detection circuit 5 and supplying a call current, and 6a is a power supply thereof. 7 is a contact 8a of the relay 8,
This is a Levers circuit composed of 8b.

Reference numeral 9 is a PB signal receiving circuit, 10 is a tone generator circuit for sending ringing tone, hold tone, etc., 11 is an exchange switch, and 12 is a controller for controlling the exchange switch 11 and the relay 8.

Next, the extension telephone 2 will be described.

Reference numeral 22 is a diode bridge for making the polarity of the electric power fed from the extension circuit 4 through the communication path 3 constant, 13 is a hook switch, 14 is a dial circuit for transmitting a PB signal, 1
Reference numeral 4a is a dial key, 15 is a communication circuit, 16 is a handset, and 20 and 21 are amplifiers and speakers as a loudspeaker. They are an amplifier and a speaker as an amplification and loudspeaker. The amplifier 20 operates by the electric power from the power feeding circuit 6 provided via the communication path 3.

Reference numeral 23 is a display circuit provided as necessary, for example, LC
A pictograph or the like showing the operating state of the extension telephone 2 is displayed by D. Reference numeral 17 is a high impedance circuit for matching, which is used for the display circuit 2 for the communication path 3.
3 has a high AC impedance and a high resistance value on the side of the amplifier 20, and even if the display circuit 23 and the amplifier 20 are connected to the communication path 3 via the switching circuit 18,
The loop resistance detection circuit 5 is configured to be distinguishable from the loop formation by off-hook described later.

Reference numeral 18a is a control input line of the switching circuit 18. 1
Reference numeral 9 is a backflow prevention diode that controls the switching circuit 18.

Next, the operation will be described.

First, normally, the polarity of power feeding by the power feeding circuit 6 is positive on the side of the terminal 3a and negative on the side of 3b, and the switching circuit 18 is in the OFF state. That is, the amplifier 20, the display circuit 23, etc. are not connected to the communication path 3.

Now, when the extension telephone 2 goes off-hook to call another extension telephone, the hook switch 13 is closed and a loop is formed by the hook switch 13, the dial circuit 14, and the communication circuit 15, so that the loop resistance detection circuit of the extension circuit 4 is formed. 5 detects it, and the detected output is output line 5a.
To the controller 12. As a result, the controller 12 controls the exchange switch 11 to connect the line 11a of the extension circuit 4 to the tone generator circuit 10 and the PB signal receiving circuit 9 and send out a DT tone to the extension telephone 2 which has performed the above-mentioned transmission operation. And prepare for receiving the dial signal. Next, in the extension telephone 2, the dial key 14a is operated to call the extension telephone to be called (extension telephone 2 shown in the figure).
Since it is the same circuit as the above, the called extension telephone set will be described below with reference to the extension telephone set 2. ), The dial information is received by the PB signal receiving circuit 9 via the extension circuit 4 and the exchange switch 11, and the received output is sent to the controller 12. As a result, the controller 12 controls the exchange switch 11 so that the line of the extension circuit 4 corresponding to the accommodation position of the called extension telephone 2, for example, the line 11n and the line 11 on the calling extension telephone 2 side.
a and the relay 8 corresponding to the extension circuit 4 on the called extension telephone side are driven to invert the contacts 8a and 8b of the levers circuit 7 so that the power feeding from the power feeding circuit 6 is positive on the terminal 3b side. , 3a has a negative polarity. As a result, a positive polarity is given to the control input line 18a of the switching circuit 18 of the called extension telephone set 2 through the diode 19, so that the switching circuit 18 is turned on and the display circuit 2
3 and the amplifier 20 are connected to the communication path 3, and the operating power from the power supply circuit 6 of the extension circuit 4 is applied to the display circuit 23 and the amplifier 20 through the diode bridge 22 to be in the operating state.

Therefore, the voice signal applied from the handset 16 of the calling extension telephone set 2 is given to the amplifier 20 of the called extension telephone set 2 through the connection path formed through the exchange switch 11 and is amplified by the speaker 21. That is, a voice call can be made. This allows the called extension telephone 2
In response to the response (off-hook), the hook switch 13 is closed and a loop is formed in the same manner as described above. 5a to controller 12
Given to. As a result, the controller 12 restores the relay 8 operated as described above, and the relay circuit 7
The contact points 8a and 8b are reversed to bring the power supply polarity from the power supply circuit 6 to the normal state described above. As a result, the control line 18a of the switching circuit 18 of the called extension telephone set 2 has a negative polarity, so that the switching circuit 18 is turned off,
The display circuit 23, the amplifier 20, etc. are disconnected from the communication path, and the off-hook handset 16 can communicate. Note that the threshold value is selected so that the loop resistance detection circuit 5 does not output the detection output due to the connection or disconnection of the communication path 3 such as the amplifier 20. Since it is provided so as to have a resistance value, it is relatively easy.

Further, in the present invention, when it is desired to use the signal ringing together, that is, when the caller selectively makes the voice ringing and the signal ringing, for example, when the calling extension telephone set 2 transmits the dial number. Before that, a predetermined selection signal (for example, “#” in the case of a voice call, immediately send a dial number in the case of a signal call) is sent out, and the signal is received by the PB signal receiving circuit 9 and is sent to the controller 12. By giving it, the controller 12 is made to identify it, and when it is "#", the lines 11n and 1
If 1a is connected and "#" is not received, the tone generator circuit 10
If the ringing tone output line is connected (so-called normal ringing connection), the ringing tone from the sound source circuit 10 is emitted from the speaker 21 and the signal tone can be called.

2 and 3 are block diagrams showing another embodiment of the present invention, but are omitted because they are the same as FIG. 1 except for the extension telephone.

2 is different from that of FIG. 1 in that power is supplied to the display circuit 23 and the amplifier 20 via the switching circuit 18 from the previous stage of the diode bridge 22 via the diode 19. This is a point, and as can be understood from the above description of the operation, the voice call and the signal tone call can be made also in FIG.

FIG. 3 shows that the display circuit 23, the amplifier 20 and the like are connected to the communication path 3 through the hook switch 13,
Since the connection with the communication path 3 is disconnected by off-hook, the amplifier 20 and the like can be immediately turned off even if the reversing circuit 5 is not inverted at the time of the response described above. In this case, the Levers circuit 7 may be inverted by the detection output of the loop resistance detection circuit 5 at the time of ending the call.

Further, it is well known in the conventional telephone exchange apparatus (for example, PBX) that functions such as holding and transferring can be realized by two-wire wiring, and therefore detailed description thereof will be omitted.

[Advantages of the Invention] As described above, according to the present invention, since the amplifier is provided on the telephone side, a telephone that can make a voice call by two-wire wiring even in a telephone exchange apparatus in which a communication path switch or the like is computerized. A switching device can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of a telephone exchange device embodying the present invention,
2 and 3 are block diagrams showing another embodiment of the present invention. 1 ... Exchange, 2 ... Extension telephone, 3 ... Call path, 4 ...
... extension circuit, 5 ... loop resistance detection circuit, 6 ... feeding circuit, 7 ... revers circuit, 8 ... relay, 9 ... PB signal receiving circuit, 10 ... sound source circuit, 11 ... exchange switch, 12 ...... Controller, 13 …… Hook switch,
14 ... Dial circuit, 15 ... Communication circuit, 16 ... Handset, 17 ... High impedance circuit, 18 ...
... Switching circuit, 19 ... Diode, 20 ... Amplifier, 21 ... Speaker, 23 ... Display circuit

Claims (1)

[Claims] 1. A telephone exchange apparatus which accommodates a large number of extension telephones so that at least the extension telephones can be selectively connected to each other, the extension telephones are connected to a communication path by an amplifier using an electric power between communication lines as an operating power source. An extension circuit of the exchange is provided with a loudspeaker that amplifies a given voice signal, a high-impedance circuit connected to the power feeding path of the amplifier, and a control means that controls the loudspeaker to an ON or OFF state depending on the polarity of the speech path. Is equipped with a loop resistance detection circuit that detects the loop resistance of the extension telephone and a reversing circuit that reverses the polarity of the communication path.The reversing circuit is driven by calling the extension telephone and the output result of the loop resistance detection circuit. Telephone exchange device characterized in that