JPH0325080B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an extension hands-free circuit in a key telephone device.

FIG. 1 shows a connection method of an extension hands-free circuit in a conventional key telephone device. In this conventional example, a hybrid amplifier 1-
1 and counting circuit 1-2 are implemented, and button telephone 2 is implemented.
Microphone 2-1, microphone amplifier 2-2, control circuit 2-3, speaker amplifier 2-4, speaker 2-
5 is implemented, the dial pulse of the extension calling signal from the calling side button telephone 3 is counted by the counting circuit 1-2, and the output is sent to the control circuit 2-3 of the button telephone 2.
input to microphone 2-1, microphone amplifier 2-2,
The called telephone 2 is activated by operating the speaker amplifier 2-4.
On the side, the telephone is configured so that a response call can be made between the microphone and the speaker with the calling telephone 3 without lifting the handset 2-6.

In the above connection method, the communication circuit 3- of the calling telephone 3 is electrically connected to the hybrid amplifier.
1, the handset 3-2, the microphone 2-1 of the called telephone 2, the microphone amplifier 2-2, the speaker amplifier 2-4, and the speaker 2-5, so the hybrid balance is connected to the button telephone device. Stable regardless of the number of phones.

However, for the connection between main unit 1 and telephones 2, 3..., there are two wires for the inner line, a total of two wires for the input/output wires of the speaker amplifier and microphone amplifier of the child unit, and an output wire for the counting circuit for the number of connected telephones. Multiple core wires will be required depending on the situation. For this reason, a multi-core cable was required to connect the main device and the telephone, but multi-core cables require difficult wiring work, high parts and construction costs, and have the serious drawback of spoiling the aesthetics of the room. Ta.

Therefore, in order to reduce the number of core wires, there is a need for a system that multiplexes and transmits information between the main device and the telephone. Its configuration is to multiplex extension calls, ringtones, information, and power onto a two-core internal line and connect it to a branch.However, in the conventional method in which a hybrid amplifier is installed in the main device, the telephone speaker amplifier and microphone are connected to each other. Since two wires are required to connect the amplifier, it is necessary to mount a hybrid amplifier on a telephone equipped with an extension handsfree function and perform 4-wire to 2-wire conversion within the telephone. However, the internal line contains internal calls, information,
Since the power is multiplexed, it is necessary to implement various filters in the main device and the telephone to extract the necessary signals. A hybrid amplifier is electrically connected to the inner line for extension hands-free operation, but the input impedance on the inner line side of the hybrid amplifier cannot be made very large due to the transmission/receiving loss. The disadvantage is that the influence of the input impedance on the inner line side of the hybrid amplifier appears.

Furthermore, if a hybrid amplifier is installed in multiple telephones, the effect becomes more pronounced, so the number of telephones that can implement extension hands-free with a button telephone device may be limited, and this may result in a serious situation where the user's requests cannot be met. There was a drawback.

The present invention provides, in an extension hands-free circuit in a button telephone device connected to a 4-core branch, a switching circuit to control the hybrid amplifier provided in the extension hands-free circuit so that it is not electrically connected to the extension line at all times. It is an object of the present invention to provide an extension hands-free circuit that can minimize the influence of the input impedance on the inner line of a hybrid amplifier on the inner line and can be implemented in a required number of telephones.

The present invention will be explained in detail below based on the drawings.

FIG. 2 shows an embodiment of the present invention, in which 10 is a main device, 11 is a station arrival detection circuit for receiving and detecting an incoming signal from a station line, 12 is a sound source, and 13 is a low-pass filter (hereinafter referred to as LPF 13). , 14 is a general-purpose microcomputer (Fujitsu MB88501, below)
14a is an input/output circuit, 14b is a control circuit, 14c is a memory circuit, 15 is a receiving circuit including an FS signal demodulation circuit, 16 is a high-pass filter (hereinafter referred to as HPF 16), 17 is an FS signal modulation circuit, 18 is a power supply, 20 is a button telephone (hereinafter referred to as a handset) No. 1, 201 is a communication circuit including a handset, and 202 is a low-pass filter (hereinafter referred to as a handset).
203 is a high pass filter (hereinafter referred to as HPF 203), 204 is a receiving circuit including an FS signal demodulation circuit, 205 is an FS signal modulation circuit, 206 is a microcomputer (Fujitsu
MB88501 (hereinafter referred to as CPU), 206a is an input/output circuit, 206b is a control circuit, 206c is a memory circuit, 207 is a speaker amplifier, 208 is a speaker, 209 is a switch circuit, 210 is a function button such as a central line button, 211 is a A display section 212 shows the usage status of the office line and extension line; 212 is a box switch information sending circuit that sends the switch on/off information to the control circuit 206b and the extension hands-free control circuit 104; 213 is a box switch button that operates when the power is turned on;
The LK relay 214, which is restored when LK is operated, is the power supply. 100 is an extension hands-free circuit, 1
01 is a microphone, 102 is a microphone amplifier, 103 is a hybrid amplifier, 104 is a control circuit 206b
The microphone 101 and the microphone amplifier 10 are activated only when the extension hands-free activation signal from the switch and the on-hook information from the hook switch information sending circuit 212 are input.
2. An extension hands-free control circuit that outputs control signals for operating the switching circuits 105, respectively;
105 are analog switches ASW1, 2, which are turned on and off by signals from the extension hands-free control circuit.
A switching circuit consisting of 3 (second switch means). Under normal conditions (standby state), ASW1 and 2 are off, and ASW3 is off.
is on to form an incoming ring loop. 106, 107, 108, 109 are the input/output terminals of the extension hands-free circuit, 30 to n are other slave units
No.2 to No.n, HA are handsets, lk0, lk1, lk2 are
LK relay contacts, HS1, HS2 are switch contacts, LT is transformer, ASW4, ASW5
(first switch means) is an analog switch that controls the input to the speaker amplifier 207 with a signal from the control circuit 206b, L1L2 is a local line, and C
1C2 is an inner line.

First, the general operation of the present invention will be explained.

First, the data transmission format between the main device 10 and the slave device 20 will be described. In a button telephone device, when transmitting and receiving information signals between the main device 10 and each handset 20 to n using a pair of transmission paths, it is common to transmit various information signals serially. The main device 10 and each child device 20 to n need to be in a synchronized state. FIG. 3 shows the information signal transmission form and synchronization method of this embodiment, which will be explained below. In the transmission form shown in 1 in FIG. 3, the synchronization signal shown in (2) is transmitted from the main device 10 to all slave units 20 to n at timing T1, and each slave unit 20 to n receives this synchronization signal. and enters a synchronized state with the main device 10. Next, at timing T2, the main device 10 transmits main device information to all slave devices 20 to n, and thereafter, at timing T3, the first slave device 20 transmits slave device information to the main device 10. Then, the second handset information is transmitted at the timing T4, and the nth handset information is sequentially transmitted at the timing Tn+2. When the transmission of the last number handset n is completed, the main device 10 again transmits the synchronization signal. All slave units 20~n
, and repeat the same process thereafter. In addition, the synchronization signal format is as shown in (2) in Figure 3, in which the main device 10 transmits a continuous high signal of 20 to nn bits to all slave devices, and then transmits a low signal as a synchronization bit. It is. The handset 20 to n side counts these consecutive high signals, confirms that they are more than a certain number of consecutive high signals, then checks the first low signal received after that, corrects the timing, and synchronizes. Take. In addition, since each slave device 20 to n confirms the synchronization signal from the main device 10, the information signal is checked even when other slave devices are transmitting. Therefore, for synchronization from the main device 10, continuous
The high signal will be a number of consecutive high signals that do not occur even when all possible states are combined, so as to distinguish it from other information signals.

The specific configuration of the receiving circuit used for the above data transmission is described in the patent application filed in 1982 by the applicant.
There is number 42123.

<Incoming call on central office line - Answer - End call> Next, we will explain the incoming call response operation on central office line.
When a calling signal from the station arrives on the station line L1L2, the signal turns on the photocoupler PC of the station arrival detection circuit 11 of the main device 10. The ON signal of the photocoupler PC is input to the control circuit 14b via the input/output circuit 14a of the CPU 14, and in the control circuit 14b, the incoming call information is sent to the inner line C1C2 along with the power supply through the input/output circuit 14a, the FS signal modulation circuit 15, and the HPF 16. It is output in a superimposed manner and sends out the central office line incoming information to all telephones. At the same time, the control circuit 14b
outputs the incoming station line information to the sound source 12, and the sound source 12
A station line ringing tone is sent to each handset through the LPF 13 and the inner line C1C2. The control circuit of each slave unit transmits the incoming station line information from the main unit 10 to the inner line C1C.
When the signal is received by the receiving circuit via 2 and demodulated into the original signal format and inputted, a high signal for operating the speaker amplifier is output from the output port θ ₀ of the control circuit 206b of slave unit No. 1, for example. ASW4
Turn on and turn ASW5 off. Control circuit 206b
Extension hands free circuit 10 from output port θ ₁ of
A high signal that turns 0 off continues from the standby state and is output to the handsfree control circuit 104 through the terminal 108 of the extension handsfree circuit 100. The extension handsfree control circuit 104, which receives a high signal from the control circuit 206b, sends a low signal to the microphone 101 and the microphone amplifier 102 to control their operation, and sends a low signal to the switching circuit 105 to perform ASW.
1. A standby state is maintained in which ASW2 is turned off and ASW3 is turned on. Therefore, the sound source 1 of the main device 10
The office line ring tone sent from 2 is input to the handset through extension C1C2, and in the handset, it is input to [extension C1C2-
It is input to the terminal 106 of the extension hands-free circuit 100 through the route LPF ₂₀₂ - lk 0.lk ₁ make contact - HS 1 break contact - lk ₂ make contact - transformer LT - extension hands-free circuit terminal 106]. In the extension hands-free circuit 100, under normal conditions, ASW1 and ASW2 of the switching circuit 105 are set to OFF and ASW3 is set to ON, so the central office line ring tone is set to ASW3.
The ring tone is output from the terminal 107 by the incoming call loop passing through the ASW 4, and the ring tone is further inputted to the speaker amplifier 207 through the ASW 4 and output from the speaker 208. In addition, the control circuits of all slave units output a blinking signal for the station line lamp to each display section, so that the station line lamp blinks are displayed when the station line is on. When you raise the handset HA on any handset (for example, handset No. 1) and press the function button 210 (station line button), the LK relay is restored and the ring tone is sent to the speaker 208 through the lk ₀ and lk ₁ contacts. The route is cut off, the station ringing stops, and the station lines L1L2 are connected to the telephone call circuit 201 and a telephone call can be made. At the same time, the station line response information is input to the control circuit 206b via the input/output circuit 206a, and the control circuit 206b inputs the station line response information to the control circuit 14b via the input/output circuit 14a of the main device 10. The control circuit 14b that has received the office line response information stops sending out the office line incoming information that was being output to each child unit, and outputs a lighting signal for the office line lamp. The control circuit of each handset to which the lighting signal has been input changes the station line lamp blinking signal outputted to the display section to a lighting signal, and turns on the station line lamp on the display section. When the call ends and the handset is hung up, the office line lamp on the display goes out and the handset returns to standby mode.

Note that in a handset in which the extension hands-free circuit is not implemented, the terminals 106 and 107 of the extension hands-free circuit are shorted, so that the sending of the calling signal from the speaker is controlled only by the control of the ASW 4.
Other operations are the same as a handset equipped with an extension hands-free circuit.

<Extension calling all at once> Next, the operation of calling all extensions at once will be explained.
For example, when trying to call another handset from handset No. 1, if you lift the handset HA without pressing the function button 210, the call circuit 201 will receive a call from [inner line side - LPF 202 - lk ₀ - call circuit 201]. −
A communication current flows through the path of HS1 _{- lk1} -LPF202-inner line side, and the extension line is captured. When an operation for calling all extensions (for example, pressing dial 0 on the switch circuit 209) is performed, the control circuit 206b detects this and sends it as an information signal to the main device 10 through the modulation circuit 205 and HPF 203. The control circuit 14b is HPF16,
When the receiving circuit 15 receives the simultaneous paging signal, it transmits extension simultaneous paging information and extension lamp blinking information to all slave units. Furthermore, main device 1
The control circuit 14b of No. 0 outputs an extension ringing tone sending signal to the sound source 12, and the sound source 12 sends out an extension ringing tone to each slave unit. The control circuit 206b of each handset that receives the extension call information operates the extension hands-free circuit 100 using the control signal from the output port θ1, outputs a signal from θ0 to operate the speaker amplifier, and turns on ASW4.
5 is off. At the same time, an extension lamp blinking signal is output to the display unit 211 to blink the extension lamp. The extension ring tone is superimposed on the extension lines C1 and C2 through the LPF 13 of the main device 10, and the extension ring tone is superimposed on the extension lines C1 and C2 through the LPF 13 of the main device 10.
2 [lk ₀ − transformer LT − lk ₂ − HS1
-lk ₁ ] to the secondary side of the transformer LT, is amplified by the speaker amplifier, and is sent out as a ring tone from the speaker 208.

The extension ring tone will be a tone call while the dial is pressed, and when the dial is released, it will switch to a voice call and the voice input from the handset will be heard from the speaker 2.
It is configured to be sent from 08.

In this state, if you lift the handset with any handset,
The switch contacts HS1 and HS2 are closed, the communication circuit is connected, a communication current flows, and an extension capture state is established, resulting in an extension communication state. In addition, contact HS2 of the switch information sending circuit 212 allows the slave unit to
The CPU detects the extension capture and sends information to the main device CPU 14. The main device CPU 14 receives this and
In order to stop the extension ringing tone, a signal is output to the sound source 12, and information about lighting up the extension lamp is transmitted to all slave units. The CPUs of all slave units receive this and output a signal to the display unit to turn on the extension lamp.
When the call ends and the handset is put down, the telephone switch cuts off the communication current in the communication circuit and opens the inner line.The handset CPU detects this through the telephone switch information sending circuit, and the main unit CPU 14 receives this and all Information on turning off the extension lamp is sent to the machine, and the CPU of the slave unit outputs a signal to the display unit to turn off the extension lamp. As a result of the above, the extension line is on standby.

<Individual extension call> Next, the extension hands-free operation, which is the gist of the present invention, will be explained.

Set handset No. 2 as the calling handset that makes the call, and handset No.
Reference numeral 1 denotes a called slave unit which is equipped with an extension handsfree circuit 100 and can respond to an extension handsfree response when receiving an individual call. Note that each handset has an extension number set in advance.

When the handset (not shown) of handset No. 2 is raised to call an individual extension, current flows through the communication circuit and the extension is captured, similar to the simultaneous calling of extensions. Here, when the extension number corresponding to handset No. 1 is dialed using the switch circuit 209, the call information is transmitted to the CPU, FS signal modulation circuit, and HPF of handset 30.
Inner line C1C via (none shown)
2, and is input to the control circuit 14b of the CPU 14 via the HPF 16 and the receiving circuit 15 of the main device 10. The control circuit 14b of the CPU 14 sends an individual calling signal (including an extension lamp blinking signal) to the control circuit 206b of handset No. 1 in response to the calling information, and outputs an extension ringing tone sending signal to the sound source 12. do. The sound source 12 sends a ringing tone to the inner line C1C2 via the LPF 13. Receiving circuit 2 of handset No. 1 that received the individual calling signal
04 demodulates the signal to the original signal format and sends it to the CPU 20
After confirming the on-hook information from the hook switch information sending circuit 212, the control circuit 206b of the CPU 206 changes the high signal sent from the output port θ1 to a low signal and operates the extension hands-free circuit 100. At the same time, a high signal is output from the output port θ ₀ to turn on the first switch means ASW4 and turn off the ASW5 to operate the speaker amplifier 207. An extension lamp blinking signal is sent from the input/output port θ ₂ to the display unit 211, causing the extension lamp to blink. Extension hands-free control circuit 104 to which the operation signal is input
is a microphone 101, a microphone amplifier 102, and a second
ASW1 and ASW2 form an extension hands-free calling loop of the switching circuit 105, which is a switching means for
A control signal is sent to turn on the ASW 3 that forms the incoming call loop and turn off the ASW 3 forming the incoming call loop, thereby setting the state in which an extension hands-free operation for making a call using the microphone 101 through the hybrid amplifier 103 can be performed. On the other hand, the extension ring tone sent from the sound source 12 of the main device 10 through the LPF 13 and superimposed on the extension line C1C2 is extracted from the LPF 202 of the handset 20 and is routed to the [lk ₀ - transformer LT - lk ₂ - HS1 - lk ₁ ]. is guided to the secondary side of transformer LT through [transformer LT-extension hands-free circuit terminal 106-
ASW1-Hybrid AMP103-ASW2-
Terminal 107-ASW4-Speaker amplifier 207-
An extension ringing tone is transmitted from the speaker 208 via the route of the speaker 208].

Through the above route, the calling handset No. 2 and the called handset No. 1 are connected.
This means that the call route between the two is now connected. Microphone 1 on called handset No. 1 without lifting the handset.
01, the response voice is [Microphone 101 of extension hands-free circuit 100 - Microphone amplifier 102 - Hybrid amplifier 103 - ASW1 of switching circuit 105 - Terminal 106 - Transformer LT -
lk ₂ make contact - HS1 break contact - lk ₀ /lk ₁ make contact - LPF 202 - inner line C1C2], it is superimposed on the inner line C1C2 and sent to the calling handset No. 2, and in the handset No. 2 LPF (not shown)
is extracted and transmitted as a response voice from a handset (not shown). Through the above route, the handset of the calling handset No. 2 and the microphone 101 of the called handset No. 1 are connected.
An extension hands-free call is made between the user and the speaker 208. Further, the extension lamp on the display unit 210 continues to blink to indicate that the hands-free call is in progress.

When handset No. 1 is picked up and answered, an off-hook signal is input from the handset switch information sending circuit 212 to the extension hands-free control circuit 104 through the terminal 109, and at the same time
06b, and the output from the control circuit 206b to the extension handsfree circuit terminal 108 changes from a low signal to a high signal, so the output of the extension handsfree control circuit 104 also becomes a low signal, and the microphone 101,
ASW1, ASW2 of microphone amplifier switching circuit 105
Turn off and turn on ASW3 to stop the hands-free function. Further, the control circuit 206b is connected to the main device 10.
Off-hook information is also sent to the control circuit 14b of the main device 10, and the control circuit 14b of the main device 10
The extension ringing tone transmission signal that was being output to the terminal will be stopped, and the extension lamp blinking information sent to each handset will be changed to lighting information. By the above operation, slave unit No.1 and slave unit No.2
A normal extension call is made through the handset and the extension lamp on the display lights up completely.

Further, in the above embodiment, the switch of the switching circuit 105 is configured as an analog switch, but it goes without saying that the switch is not limited to this and may be configured using other switching means (for example, a relay, etc.).

As is clear from the above explanation, according to the extension hands-free circuit of the present application, depending on the input state of the central office line incoming signal, all extension ringing signal, individual extension ringing signal, and office switch on-off signal, an extension handsfree control circuit that outputs a control output; a microphone, a microphone amplifier, and a hybrid amplifier that operate based on the output signal from the extension handsfree control circuit;
A switching circuit is provided which is configured to provide a switch means for forming an incoming call loop during standby and for cutting off the incoming call loop and forming an extension hands-free calling loop during extension hands-free operation, and a signal input to the control circuit. only when an on-hook signal and an extension individual calling signal are input, the microphone, microphone amplifier, and switching circuit are operated and switched, and the extension communication path and the hybrid amplifier are connected to make a call, and the input signal is input. Since the switching circuit is configured so that the hybrid amplifier is not connected when the signal is other than an on-hook signal or an individual extension call signal, the hybrid amplifier and the extension communication path are connected only when the individual extension call is received. The circuit configuration is such that the influence of the input impedance of the hybrid amplifier on the inner line can be reduced because the call is limited to only the telephone that received the call and the time that the call is being received.

As explained above, according to the present invention, a switching circuit is provided so that the hybrid amplifier provided in the extension hands-free circuit is not electrically connected to the extension line at all times, and the connection route is controlled according to the call state. Therefore, the influence of the input impedance on the inner line side of the hybrid amplifier on the inner line can be minimized, and even when applied to an extension hands-free circuit in a 4-pin branch-connected button telephone device, there is little effect on the inner line. Furthermore, it has the excellent advantage of being able to implement an extension hands-free circuit in any number of devices.

[Brief explanation of the drawing]

Fig. 1 is a connection diagram of a conventional extension hands-free circuit, Fig. 2 is a circuit diagram showing an embodiment of the present invention, and Fig. 3 is a circuit diagram showing an embodiment of the present invention.
The figure is a time chart for explaining signal transmission according to the present invention, and FIG. 4 is a flow chart showing hands-free operation. 10... Main device, 11... Station arrival detection circuit, 12
...Sound source, 13...LPF, 14...Microcomputer, 15...Reception circuit, 16...HPF,
17...FS signal modulation circuit, 18...Electric wire, 20
...Telephone No. 1, 201...Telephone circuit, 202...
...LPF, 203...HPF, 204...receiving circuit,
205...FS signal modulation circuit, 206...Microcomputer, 207...Speaker amplifier, 2
08...Speaker, 209...Switch circuit, 2
10...Function button, 211...Display section, 212
...Full switch information sending circuit, 213...
LK relay, 214...power supply, 100...extension hands-free circuit, 101...microphone, 102...
Microphone amplifier, 103...hybrid amplifier,
104...Extension hands-free control circuit, 105...
...Switching circuit, 106-109...Input/output terminal.

Claims (1)

[Scope of Claims] 1. A button telephone device in which a plurality of button telephones are connected in parallel to a main device via an extension communication path, each of the button telephones having a microphone, an amplifier for amplifying the output of the microphone, A hybrid circuit connected to the output side of the amplifier, a switching circuit provided with switch means in the input/output path on the extension communication path side and the output path on the speaker side of the hybrid circuit, and an an extension hands-free control circuit that switches and controls a switch means of the switching circuit to connect the hybrid circuit and the extension call path when the extension call signal is received; An extension hands-free circuit in a button telephone device, characterized in that it is configured to allow hands-free calls.