JPS5950156B2 - Extension calling method for button telephone equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a button telephone device, and more particularly to a button telephone device suitable for small businesses or residences.

Conventional button telephone devices of this type are configured to be wired using multi-core cables with about 20 core wires, so wiring work is not easy, and the placement of multi-core cables does not affect the aesthetics of the room. This had the drawback of not only causing losses but also increasing construction costs.

In order to eliminate these drawbacks, it is desired to reduce the number of core wires in the distribution cable, but conventionally information between the main device and each slave device was transmitted in parallel within a multi-core cable. Therefore, when reducing the number of core wires, it is necessary to multiplex and transmit this parallel information. However, if all the information is multiplexed and transmitted over the information line, the configuration of the circuit used for information transmission becomes complicated and the cost increases. SUMMARY OF THE INVENTION An object of the present invention is to provide an extension calling system for a button telephone device that can reduce the number of core wires of a distribution cable with a relatively simple circuit configuration.

The present invention will be explained in detail below.

First, the principle of the entire system of the key telephone device according to the present invention will be explained.

In the present invention, information from the main device to the slave device and information from the slave device to the main device are divided into two blocks, and lamp and amplifier operation information from the main device to the slave device is multiplexed and sent to the information line. We decided to use the telephone line to send button selection, hold, and dial information from the handset to the main unit. The communication current of the telephone line is varied by a constant current circuit in the handset, and button selection, hold, and dial information are identified by a detection circuit in the main unit. Putting the above together, 2 central lines and 1 extension line
The table below shows the case of a button telephone device that accommodates lines and connects three handsets. Table 1 clarifies the information and transmission routes, and Table 2 shows an example of the relationship between the status of each handset and the communication current with respect to information sent over the communication line. The basic matters used in the present invention, including the type of transmission line, are listed below.

(1) The communication path is selected by switching one line at a cross point using SCR. (2) The selection of office line 1, office line 2, and extension line is made by identifying the difference in communication current.

(3) The determination of the communication current in order to accurately detect the difference in communication current in the second term is performed by a constant current circuit using an operational amplifier in the handset.

(4) When using the cross-point switching method using SCR, transmission of dial pulses from slave units is an extremely difficult problem.

In the case of a normal telephone, when the communication current is cut off during dialing, the holding current of the SCR is cut off, and the formed cross point is canceled. In order to solve this problem, by controlling the constant current circuit on the handset side, even when the current is cut off by the dial, a talking current similar to the self-holding current of the SCR cross point will flow, and when the dial is connected, a predetermined talking current will flow. The difference is identified within the main device and the pulse is relayed to the line. (5
) When the hold button is pressed, the constant current circuit in the handset is controlled to increase the call current by about 20 mA compared to the normal call current, and this is detected.

(6) When there is a handset detection output on both the office line and the extension line and the trunk is empty, a trigger is input to the cross-point SCR to capture the line; otherwise, the line is not captured and the communication is confidential. (7) Individual extension calls and simultaneous calls to handsets are made using the dial digits.

(8) In the main device, voice calling of extension lines, transmission of incoming tone, etc., and selection of handset are performed by cross-point control.

(9) Information transmission via the information line is unidirectional from the main device to the slave device, and is performed by time division multiplexing.

Regarding the information content, 3 bits are used for the lamp information of the office line 1, office line 2, and extension line, and 1 bit is used for the amplifier operation information, so a total of 4 bits constitutes one frame. Based on the above principles, the transmission of information between the main device and each child device will be explained in more detail.

First, since the dial pulse transmission method is adopted, it is necessary to relay the dial pulses sent from the slave units to the line within the main unit.

In addition, since SCR crosspoint control is used to connect the handset and the central office line trunk, if the dial pulses caused by connecting and disconnecting the call current are sent directly from the handset to the main unit as in conventional telephones, the call current will be reduced. When the SCR is disconnected, the holding current of the SCR is lost, so the SCR is restored and the call loop is broken. In order to solve this problem, even when the call current is interrupted during dialing, a current of about 7 mA, which is higher than the holding current (5 mA) of the SCR, flows, and when the call current is connected, the call current (40 or 30 mA) is passed.
is streamed as is, the difference is detected and relayed to the line. 1st
The figure shows the change in communication current and the detection level of the office line detection circuit when dialing the office line 1 from the handset.

Regarding station line hold, the constant current circuit of the handset is controlled so that when the hold button of the handset is pressed, the call current increases by 20 mA from the normal call current, and this increase is detected within the main device.

On the information line, a total of 4 bits of information, 3 bits of lamp information and 1 bit of amplifier operation information, sent from the main device to the slave device are time-division multiplexed and sent.

Regarding the synchronization method, it is impossible to send the synchronization signal over a separate line, and since the start-stop synchronization method would complicate the circuitry of the handset, it is decided to send the information signal and the synchronization signal at the same time.

The synchronization signal is sent as a pulse with a level of about 10V, and the information signal is sent as a pulse with a level of about 24V superimposed on the synchronization signal, and the synchronization pulse and the information pulse are separated and used in the slave unit. Regarding the reset pulse, approximately 8 bits per frame are used for the information amount of 4 bits on the information line, and 4 bits are used for each frame.
As for the bit, there is also no synchronization pulse, and a reset pulse is generated within the handset when synchronization pulses are not present continuously. FIG. 2 shows an overview of the information content of the information line and the information processing within the handset.

In accordance with the above principle, the button telephone device according to the present invention can be constructed as shown in FIG.

The main device and each slave device #1, #2, #3 are connected by four wires. The four lines are a power (+) line P, a communication line T, an information line J, and a power (-) line G from the top of FIG.

Power is sent through a power (+) line P and a power (-) line G, and communication current is sent through a power (+) line P and a communication line T. Also, depending on the difference in the current flowing through the communication line T, information is sent from the slave device to the main device. Information sent from the main device to the slave device is sent as a 4-bit multiplexed signal through the information line. An incoming tone signal indicating an incoming call from the office line and a voice signal when an extension is called are sent through the communication line T and the power (-) line G, and are sent to the handset amplifier 24.
The signal is amplified and sent out from the speaker 25. The lamp status signal from the main device to the slave unit and the signal for operating the slave unit amplifier are as follows: [Slave unit lamp control circuit 9 → Incoming tone circuit 10 →
Parallel/serial conversion circuit 14→information line J→serial/parallel conversion circuit 23], each lamp 31, 3 in each slave unit
2, 33 and slave amplifier 24. Button selection information from slave unit to main unit, information on station line capture and abandonment,
Dial information and hold information are transmitted by controlling the call current to a set current value using the call current control circuit 21 in the handset and button or dial operations, and transmits the call current to a set current value by each handset detection circuit 8-1, 8 in the main unit. -2, 8-3, the detection circuit 2-1-2 of the office line 1, the detection circuit 2-2-2 of the office line 2, and the extension detection circuit 3-2 identify and control the main device. Since the button selection information is information before the cross point is formed by SCR, the slave device detection circuits 8-1, 8-2, 8-
3, the output forms an SCR cross point, and each trunk 2-1 of the central office line 1, central office line 2, and extension line 2-1,
It is connected to each station line at 2-2 and 3. S.C.
When a cross point is formed by R and a communication path is established, handset detection circuits 8-1, 8-2, and 8-3 are separated from the communication path, and instead detect each of the office line 1, office line 2, and extension line. circuit 2
-1-2, 2-2-2, 3-2 are in operation state,
Identifies and controls dialing information, hold information, and abandonment information of central office line extensions. FIG. 4 shows a specific example of the main device in the embodiment of FIG. 3, and FIG. 5 shows a specific example of the slave device.

Next, the operation of the basic functions will be explained.

(Operation of station line transmission) When the station line 1 button of handset #1 is pressed and the handset of the handset is up, the lift switch HS is activated, and the operational amplifier 0P is activated.
A talking current of 40 mA is determined by the resistor R203 of the constant current circuit constituted by the transistor Tr201 and the transistor Tr201 and R204 selected by the button switch LK1, and this is determined by [telephone circuit network TEL → switch LK1 → switch HS → BS contact → from the telephone line T#1] to the telephone line T.

In the main device, the output of IC4 is low and no current flows through the photocoupler PD1, so the transistor Tr1 connected to it is OFF, and the 0R circuit 1C2 and N
Through the OT circuit 1C3, the transistors Tr2 and Tr3
is in the ON state. Here, when a communication current of 40 mA flows from the handset, the communication current flows to the resistor R3 through the transistor Tr3, and a voltage corresponding to 40 mA is generated across the resistor R3. Comparator Comp1 in slave device detection circuit 8-1 operates, and its output is input to AND circuit 1C9. In addition, in the detection circuit 2-1-2 of the office line 1, the communication current flows through the transistor Tr3 and the resistor R3, and the transformer LTCO
1 and resistor 8, so the comparator Com
p4 is OFF and its output is 10W. The output of the comparator Comp4 passes through the NOT circuit 1C54 and is applied to the AND circuit 1C9. That is, when the trunk 2-1 of the central office line 1 is not in use, the handset detection circuit 8-
When an output to capture station line 1COL1 is added from 1, AN
The D circuit 1C9 is set to a high output and triggers the gate of the SCR of S1 that connects the handset #1 and the office line trunk 2-1. At the same time, the High output of AND circuit 1C9 is
[OR circuit 1C4 → 0R circuit 1C2 → NOT circuit 1C3
] The transistors Tr2 and Tr3 are turned 0FF through the path
The communication current is [Resistor R4 → Photocoupler PD1 → S
1 SCR→office line 1 transformer LTCO1→resistor R8]. When a communication current flows through the photocoupler PD1, the transistor Tr1 turns on, and [NOT circuit 1
C1→OR circuit 1C2→NOT circuit 1C3], the transistors Tr2 and Tr3 are kept OFF. When the communication current flows through the resistor R8, a voltage is generated across the resistor R8, the comparator Comp4 operates, and the high
h output turns on transistor Tr5, and relay A
1 works. By the contact a1-1, the central line 1COL1
The line is closed, and handset #1 completes acquisition of office line 1 through office line 1 transformer LTCO1. Also, when the A1 relay operates, the data selector IC6 is activated by the contact a1-2.
Since the lamp signal of the station line 1 applied to the terminal 4 of the information line J(7) becomes High, the information line LD1 information of the information line J(7) becomes High after parallel-to-serial conversion by the parallel-to-serial conversion circuit 14. This signal is sent to the slave unit through the information line J, and the comparator C
omp201. The signal is separated into a synchronization pulse and an information pulse by the Comp202, and converted into serial/parallel by the serial/parallel conversion circuit 23, turning on the transistor Tr202 and lighting the lamp LD1. Here, when handset #1 makes a dial call, contact DP1 opens and closes due to the dial, and contact DP
When 1 is open, the resistor R204 of the slave unit constant current circuit is the contact DP.
1, and the communication current is 10 mA determined by the resistor R203.

When the contact DP1 is closed, the current is 40 mA, similar to when talking. Also, contact DP2 connects telephone circuit T during dialing.
Short-circuiting EL not only prevents noise from the receiver due to intermittent current, but also prevents disturbance of the waveform of intermittent current caused by telephone circuit TEL(7)L,C. The intermittent current generated by the dial is sent to the main device through the telephone line T, and this is transmitted to the main device through the telephone line T#1 → resistor R4 → photocoupler PD1 → SCR of S1 →
A voltage pulse is generated across the resistor R8. This voltage pulse is detected by comparator Comp5, and when the communication current is 15 mA or less, comparator Comp5 becomes Hi.
Outputs gh output. The output of comparator Comp5 is N
The transistor Tr6 is turned ON through the OT circuit 1C12 and the AND circuit 1C13, and the D1 relay is turned ON. The contact d1-1 of the D1 relay sends a dial pulse to the line. Since a minimum call current of 7 mA is ensured even during dialing, the current flowing through SCR of S1 is SC
The minimum holding current of R becomes 5 mA or more, and the SCR maintains the ON state. When the dialing is completed, the call to the other party is made through the transformer LTCO1. While handset #1 is talking through central line 1, handset #2 attempts to interrupt central line 1 and interrupts central line 1.
When you press the button and raise the handset, handset #2 becomes handset #1.
It operates in the same way as above, and a predetermined communication current is passed from the handset side to the communication line T.
Send it to the main device through #2.

At this time, in the main device, since the transistors Tr9 and Tr10 of the child device detection circuit 8-2 are in the ON state, a communication current flows to the resistor 15 through the transistor Tr10, and a voltage is generated across the resistor 15, which causes the comparator Co
mp7 operates and the output of comparator Comp7 is AN
It is input to D circuit 1C10. However, at that time, station 1 transformer LTCO1 is being used by handset #1, so the communication current from handset #1 flows into resistor R8 in the detection circuit 2-1-2 of station line 1, and the communication current from handset #1 flows into both ends of it. Voltage is present. Therefore, the comparator Comp4 operates, and its output is input to the AND circuit 1C10 through the NOT circuit 1C54. Since this input is at a low level while transformer LTCO1 is in use, AND circuit 1C10 does not open even if there is an output from slave unit #2 and station line 1 transformer 8-2. SC of S2 joining LTCO1
No trigger pulse is applied to R, and slave unit #2 and office line 1 transformer LTCO1 are not coupled. By the above-described operation, the confidentiality of the telephone call on the central office line 1 of the handset #1 is protected. Here, handset #1
When the station handset is put down, the communication current disappears due to the switch HS (7) being turned off, and the holding current in the SCR of S1 that connects the station trunk and handset #1 disappears, and S1 is restored.

When S1 is restored, the voltage across resistor R8 disappears, comparator Comp4 turns OFF, and transistor T
r5 turns OFF. Relay A1 is restored by turning off transistor Tr5, and its contact a1-1 is opened to open the line. When relay A1 is restored, the station line 1 lamp information is turned OFF by contact a1-2, and this information is transmitted in parallel and
After being parallel-to-serial converted by the serial conversion circuit 14, it is sent to each slave unit through the information line, and the office line 1 lamp of each slave unit is turned off. As described above, handset #1 acquires central line 1 from the state in which the handset is initially placed, but when using a key telephone, for example, immediately after the telephone call on central line 2 or an extension ends, When acquiring central office line 1, the acquisition circuit may be changed by pressing directly from the central office line 2 or extension button to the central office line 1 button without putting down the handset.

The operation of this device at this time is as follows. Assume that the button for the office line 2 is now switched to the button for the office line 1. While the station line 2 is captured, [power (+) line P → constant current circuit → telephone circuit TEL → switch LK2 → switch LK1 → foot switch HS-+BS contact → talking line TI1) → resistor R
4 → Photocoupler PD1 → SCR of S4 → Transformer LTCO2 of office line 2 → Resistor R20 → Earth], and when office line 2 is captured by transformer LTC02, the switch of office line 1 button is activated. When LK1 is turned on, it is linked to the central office line 1 button and B on that call path is activated for a moment.
The S contact opens and the communication current is cut off. Therefore, the cross-point thyristor S4 is restored. Also, since the communication current is cut off, the photocoupler PD1 is turned off and the retransistor Tr1 is turned off. O of transistor Tr1
By FF, [NOT circuit 1C1→OR circuit 1C2→
NOT circuit 1C3] through the path of transistor Tr2.
is turned ON, and the transistor Tr3 is turned ON. Since the BS contact momentarily turns OFF and then immediately turns ON, the communication current determined by the contact LK1 of the office line 1 button and the resistor R204 is as follows: [Power supply (+) line P → constant current circuit → telephone circuit TE
L→Switch LK1→Hook switch HS-+BS contact→Talking line T#1→Transistor Tr3→Resistor R3→Ground], and thereafter operates in the same way as the acquisition operation of the office line 1 described above. (Operation of incoming call on central office line) When an incoming call is received on central office line 1 and a ringing signal is added, relay R1 operates through capacitors C14 and C15, and its contact r1-2 causes the output of OR circuit 1C66 to go high, and data selector IC67 The handset amplifier operation information applied to terminal 7 of is in the ON state.

This information is parallel-to-serial converted by a parallel-to-serial conversion circuit 14 and sent to each child unit through an information line J. On the handset side, the information is serial-parallel converted by the serial-parallel conversion circuit 23, and the transistor Tr205 is turned on to operate the C relay. The amplifier circuit output is connected to the speaker 25 through the contact C, and the amplifier circuit becomes operational. Further, the incoming tone circuit 10 is operated by the r1-2 contact, and the tone ringer signal is amplified by the AMP circuit 11 and input to the tone sending transformers T, T. One end of the secondary side of the transformer is given a potential of about 5V by Zener diode ZD4, and the other terminal is connected to the communication lines T#1, T#2, and T#3 of all slave units through diodes D6, D7, and D8. It's connected.
Now, when handset #1 is not in use, current flows through the path [+5V → transformer T, T → diode D6 → talking line T#1 → hook switch HS → resistor R208], and diode D6 is in the ON state. The tone ringer signal is superimposed on this path and transmitted to slave unit #1, and the tone ringer signal is transmitted to slave unit #1.
4, and the speaker 25 sounds. In addition, when handset #2 is in the middle of a telephone call on the central office line, the communication current is
#2 → Photocoupler ZD2 → SCR of S5 → Transformer LTCO2 of station line 2 → Resistor R20], so diode D7 is reverse biased and turned off.
No tone ringer signal is sent to the communication line T#2 of the handset #2. By the above operation, only the speaker 25 of the handset that is not in use is made to sound without affecting the call in use. In addition, for a handset set in advance to stop the station-arriving signal, a diode D6, which connects the communication line of the handset, is connected.
It is also possible to stop the station ringing tone by not implementing D7 or D8. When the relay R1 operates, its contact r1-1 causes the oscillation circuit 0S in the slave lamp control circuit 9 to
A 2HZ square wave signal oscillates at C (2HZ), and a 2HZ intermittent signal is added to the station line 1 lamp information by the AND circuit IC60 and the OR circuit 1C64.

This is converted into parallel/serial and sent to each handset through the information line J, converted into serial/parallel, and the station line 1 lamps of all handsets flash at 2Hz. Here, when handset #1 presses the station line 1 button and raises the handset, the station line oscillates and the output of handset detection circuit 8-1 and station line detection circuit 2-1 of station line 1 are activated. 2
Station line 1 transformer LTCO1 and handset #1 according to the status output of
Add a toj to the SCR gate of S1 that combines
Turn S1 ON.

The communication current flows through the path of [handset #1→talk line T#1→resistance R4→photocoupler PD1→SCR of S1→transformer LTCO1→resistance R8], and the voltage generated across resistor R8 operates comparator Comp4. At the output, the transistor Tr5 is turned on and the relay A1 operates. Rire A
1 is activated, the line of the central office line 1 is closed by its contact a1-1. When the central office line 1 is closed, the calling signal is stopped, so the relay R1 is restored, the tone ringer signal is stopped by the contact r1-2, and the amplifier ON information to each slave unit is sent to the terminal 7 of the data selector IC 67. It becomes OFF,
The 2Hz intermittent signal of the station line 1 lamp is A by contact r1-1.
Since it is blocked by the ND circuit 1C60, it becomes a continuous signal and the OR
The station line 1 lamp information becomes continuous lighting information through the circuit 1C64. The operation 0FF signal of the slave amplifier and the lighting information of the office line lamp are sent to the slave unit through the information line J, and all slave amplifiers are stopped.・The station line 1 lamp will be lit continuously. The operation for terminating a call is the same as for making a call to a central office line. (Operation of Holding and Reacquisition of Local Line) Next, the operation of holding and reacquiring after a call with the local line will be explained.

Assume that the caller presses the hold button while handset #1 is talking on the local line using central line 1.

When the hold button is pressed, the station line 1 button does not recover, and when the hold button recovers, station line 1. The structure is such that the buttons are also restored at the same time. Therefore, when the hold button is pressed, a resistor 207 is added by the HK contact in addition to the current determining resistors R203 and R204 of the constant current circuit, so the current flowing through the resistor R207 is added to the normal call current.
The value of resistor R207 is determined so that this increase will be approximately 20 mA. Further, at this time, the HK contact short-circuits the telephone circuit TEL to prevent a voltage drop due to the telephone circuit TEL. The increased communication current is sent to the main device through the communication line, [communication line T#1 → resistor R4 → photocoupler PD1 → S
SCR 1 → transformer LTCO 1 → resistor 8], and the voltage across resistor R8 increases. The comparator Comp6 detects this voltage increase, and its output turns on the transistor Tr7 to operate the H1 relay.
When the H1 relay operates, the line is closed by the contact h1-1 and the resistor R42 due to the operation of the contact h1-1. If you release the hold button at this point, the central office line 1 button is restored along with the hold button, so the call current disappears and the S1 SCR
is turned off, and the voltage across the resistor R8 disappears. When the voltage disappears, the comparators Comp4 and Comp6 are turned off. Comparator Com
The A1 relay is restored by the output of p4, and its contact a1-1 is closed. Also, the transistor Tr7 is turned off by the output of the comparator Comp6, but the H1 relay is connected to the contact h1-.
2 and contact a1-3, and is held in a suspended state. A
When the 1 relay is restored and the H relay operates, the AND circuit 1C62 and the OR circuit 1C6 are activated by the contacts h1-3 and a1-2.
4 turns on, the station line 1 lamp information changes from continuous information to a 1/2Hz intermittent signal, which is sent to each slave unit through the information line J, and the station line 1 lamp of each slave unit changes from continuous lighting to a 1/2Hz intermittent signal. Changes to 1/2Hz blinking. In this state, when handset #1 presses the station line 1 button again to raise the handset and go to reacquire, the A1 relay operates in the same way as when making a station line call.
The line is closed by the transformer LTCO1 through the contact a1-1.

Also, the H1 relay is restored by the contact a1-3, and the AND circuit 1C62 and the OR circuit 64 are turned off by the contacts h1-3 and a1-2, so the station line 1 lamp information changes from a 1/2 Hz intermittent signal to a continuous signal. , the station line 1 lamp of each handset changes from blinking to continuously lighting. Termination of the call is the same as for the central office line originating operation. (Extension call and extension call) When the extension button of handset #1 is pressed and the handset is raised, switch LK3 operates a constant current circuit with resistors R203 and R206, and a call current of 20 mA flows. (+) wire P → constant current circuit → telephone circuit TEL →
The signal is sent to the main device through the path of switch LK3 → switch LK2 → switch LK1 → switch HS → BS contact → communication line T#1].

In the main device, since the transistor Tr3 is ON, a voltage flows from the communication line T#1 to the transistor Tr3 and the resistor R3, and a voltage is generated across the resistor R3. This voltage operates comparator Comp3, and AND circuit 1C8
The signal is input to the AND circuit 1C35 through the gate. Also, when the extension transformer IT is not used, the extension detection circuit 3-2
No current flows through the resistor R39 inside the comparator Comp1.
6 is not operating, it is input to the AND circuit 1C35 through the NOT circuit 1C41 and the OR circuit 1C38. Therefore, the AND circuit 1C35 opens and triggers the gate of the SCR of S7 for coupling the handset #1 and the extension transformer IT, turning S7 ON. AND circuit 1C35
The outputs of 0R circuit 1C4, 0R circuit 1C2 and NO
It is added to the transistor Tr2 through the T circuit 1C3, and the transistor Tr2 is turned off and the transistor Tr3 is also turned off.
It becomes F. The communication current that was flowing through the transistor Tr3 and the resistor R3 is transferred to the SCR of S7 when the transistor Tr3 is turned off.
is ON, so [Talking line T#1 → Resistor R4 → Photocoupler PD1 → SCR of S7 → Extension transformer IT → Resistor R39
]. Since the communication current flows through the photocoupler PD1, the transistor Tr1 is turned ON, and the transistors Tr2 and Tr3 are kept OFF through the path [NOT circuit 1C1→OR circuit 1C2→NOT circuit 1C3]. Since a communication current of 20 mA flows through the resistor R39, the voltage across the resistor R39 operates the comparator Comp16.
The output of the comparator Comp16 turns on the extension lamp information, and this information is converted into information by the parallel/serial conversion circuit 14 and sent to each child unit through the information line J. In each slave device, comparator Comp201, Comp
After being separated into a synchronization pulse and an information pulse at 202,
The serial/parallel conversion circuit 23 converts the information into parallel information, turns on the transistor Tr204 through the resistor R212 and the Schmitt trigger C207, and lights up the extension lamp. Next, when handset #1 is dialed for individual calling or simultaneous calling, the following operations occur.

(1) In the case of individual calling, when the call current is interrupted by dialing, the constant current circuit on the handset side is connected to the resistor R2 by contact DP1.
06 is disconnected and the communication current is 7mA due to resistor R203.
Therefore, when the dial is connected, resistor R206 connects to contact DP1.
Since the terminals are connected by , a current of 20 mA, which is the same as the communication current, flows.

This intermittent current is sent to the main device through the communication line T#1, [communication line T#1 → resistor R4 → photocoupler PD1 →
A current flows through the path from SCR of S7 to extension transformer T to resistor R39, and the voltage across resistor R39 changes. Comparator Comp17 detects this, [NOT circuit 1C53 → AND circuit 1C50 → counter IC49]
The signal is input to the decoder IC 48 through the path. When the output corresponding to the dial is output to the decoder, if the output is black 2, [AND circuit 1C46 → OR circuit 1C4
3 → Resistor R32 → Diode D4 → Extension transformer IT →
A calling current flows through the path of the resistor R39], and the diode D4 is turned on. By turning on the diode D4, the audio signal of the handset #1 is transferred from the handset #1 to the communication line T#1.
→Capacitor C1→SCR of S7→Diode D4→Capacitor C9→Capacitor C4→Talking line T#2→Hook switch HS→Capacitor C202→AMP25→Speaker 25] The ringing sound of handset #1 is sent from the speaker 25. Ru. When the decoder IC48 outputs an output, the decoder output turns on the amplifier operation information through the OR circuit 1C52 and the IC66. This information is information line J
The signal is sent to the slave units through the C relay and operates the amplifier 24 of each slave unit. Also, while calling, decoder IC4
From the output of 8 [AND circuit 1C64 → OR circuit 1C43
→0R circuit 1C39→AND circuit 1C36], a high level is applied to the trigger gate input of the cross point SCR for the extension of the called slave unit.

When handset #2 responds to the call, the call current 2 is determined by resistors R203 and R206 in the constant current circuit.
0mA is [power (+) line P → constant current circuit → telephone circuit TEL → switch LK3 → switch LK2 → switch L
K1→Hook switch HS-) BS contact→Talking line T#2
] to the main device. Transistor Tr10 is O
Since it is in the N state, the communication current flows through the transistor Tr10.
The voltage flows through the resistor R15 through the resistor R15, a voltage is generated across the resistor R15, and the comparator Comp9 operates. The output of comparator Comp9 is input to AND circuit 1C36 through AND circuit 1C21. Now, AND circuit 1
High is applied to the other input of C36 from the output of decoder IC48 through the path [AND circuit 1C46 → OR circuit 1C43 → OR circuit IC39], so AND circuit 1C36 is opened and the connection between slave unit #2 and the extension transformer is applied to the other input of C36. Apply a trigger to the SCR gate of S8 that connects IT and turn on S8. The output of the AND circuit 1C36 is [OR circuit 1C17 → 0R circuit 1C15 → NOT circuit 1
C16], the transistor Tr9 is turned off, and the transistor Tr10 is also turned off. When the transistor Tr10 is turned off and the SCR of S8 is turned on, the communication current flows through the path of [communication line T#2→resistor R16→phototransistor PD2→SCR of S8→extension transformer IT→resistance R39]. When the voltage across resistor R39 increases, comparator Comp18 operates and NO
The output of the counter IC49 is reset through the T circuit 1C51, and the output of the decoder IC48 is stopped. Therefore, the calling diode D4 is in the OFF state, and the
Since the output of the R circuit 1C52 disappears, the amplifier operation information becomes OFF. Since the amplifier information has been turned off in the slave device, the C relay is restored and the slave amplifier 24 is stopped. Here, since the SCRs of S7 and S8 of handset #1 and handset #2 are ON, handset #1 and handset #2 are connected by the extension transformer IT, and are in a state of mutual communication.

When the call ends and handset #1 and handset #2 both put down their handsets, the call current disappears and the SCRs of S7 and S8 are restored.

When the SCRs of S7 and S8 are restored, the voltage across resistor R39 disappears, so comparators Comp16 and Com
p18 turns OFF, and comparator Comp16 turns OFF.
The extension lamp information is turned OFF by FF, and the extension lamps of each handset are turned off. (2) In the case of simultaneous calling, when the dial number for simultaneous calling is ゜゜0'' and the output of decoder IC48 is ゜゜0゛, OR circuit 1C42,
Diode D3 for calling through IC43 and IC44
, D4, and D5 are all turned on, and the calling voice from handset #1 is sent to the communication lines of all handsets through diodes D3, D4, and D5, and amplified by handset amplifier 24.
It is transmitted from the speaker 25.

In addition, the output "0" of the decoder IC48 adds High to the gate IC (AND circuit) input for triggering each SCR, and no matter which handset captures the extension and responds, the communication path is connected to the extension transformer IT, and the slave A communication path is formed with machine #1. When the communication path is established, the output of the decoder IC 48 disappears as in the case of an individual call, and all handsets other than those in mutual communication are disconnected from the extension transformer IT. The end of the extension call is the same as for individual calls.

Although the above example has been described in which two central office lines, one extension line, and three slave units are accommodated, the present invention is not limited to this example, and generally accommodates three or more central office lines and two extension lines. Of course, it can also be applied when accommodating more than 4 lines and 4 or more handsets, and depending on the number of lines and handsets required, the main device and the detection circuit and selection circuit in the telephone set may be required. This can be realized by making some changes.

As described above, according to the present invention, the slave unit detection circuit (8-1, 8-
2, 8-3) and cross-point thyristors (S7, S8,
S9) and the audio gate (D3, C8, R30; D4, C9, R32: D5
, C10, R34) and a thyristor control circuit (IC35, IC36, IC37, R) that turns on the cross-point thyristor in response to the output of the child unit detection circuit.
29, R31, R33), an extension detection circuit (3-2) that captures an extension and detects dial pulses, and counts dial pulses using the dial detection output of the extension detection circuit and outputs them to the terminal corresponding to the dial number. Decoder (IC4
8) and an amplifier operation signal sending which causes an amplifier operation signal to be sent to the information line (J) between the main device and each slave unit to activate the calling amplifier (24) of the slave unit when the output of the decoder is output. means (IC52, IC66, IC67), when the extension button of the handset is pressed, the corresponding crosspoint thyristor is triggered by the output of the handset detection circuit and the thyristor control circuit, and the handset and the extension are When the called handset number is dialed, the decoder output opens the voice gate connecting the called handset and the extension trunk, and the voice gate connecting the called handset and the extension trunk is connected to the extension trunk, and when the called handset number is dialed, the voice gate connecting the called handset and the extension trunk is opened, and the voice gate connecting the called handset and the extension trunk is opened. A button telephone device characterized in that a voice signal is sent to a communication path of a called handset, is amplified by the amplifier in the handset, and is emitted from its speaker (25) to make a call. It is possible to realize an extension calling method in

Here, the audio gate includes, for example, diodes (D3, D4, D5) and a capacitor (C) connected in parallel with the crosspoint thyristor (S7, S8, S9).
8, C9, C10) connected in series, and the connection point between the diode and the capacitor is a resistor (R30, R32, R3
4) is configured to be connected to the decoder (IC48) output via the decoder output, and the diode is turned on by the decoder output, and the calling audio signal is transmitted to the handset via the diode and the capacitor. It is configured to be sent to the road.

Furthermore, when the voice gate is opened by the output of the decoder, the decoder output is applied to the thyristor control circuit, and when the called telephone answers, the output of the handset detecting circuit corresponding to the handset is applied to the thyristor control circuit. By applying a voltage to the thyristor control circuit, the cross-point thyristor connecting the responding handset and the extension trunk is triggered to form an extension communication path, and the audio gate is closed by the extinction of the decoder output, and the amplifier is activated. It is configured to stop sending signals.

As explained in detail above, the present invention not only has the effect of reducing the number of core wires of a distribution cable, but also enables voice calls to be made to each handset, and also enables the voice call circuit to be The start and stop of operation can be easily controlled from the main device.

[Brief explanation of the drawing]

FIG. 1 is a waveform diagram for explaining the transmission of dial pulses in the button telephone device according to the present invention, FIG. 2 is a waveform diagram for explaining the transmission of information in the button telephone device according to the present invention, and FIG. 1 is a block diagram showing the main configuration of the button telephone device according to the present invention, and FIGS. 4 and 5 are circuit diagrams of the main device and the telephone, showing detailed circuit configuration examples of the button telephone device according to the present invention.

Claims (1)

[Scope of Claims] 1. A communication path connecting each slave unit and the main device includes a slave unit detection circuit that monitors the communication current through a transistor and outputs an output corresponding to the communication current, and a communication path between each slave unit and the extension trunk. a cross-point thyristor for connecting the thyristor, an audio gate placed in parallel with the thyristor, a thyristor control circuit that turns on the cross-point thyristor in response to the output of the handset detection circuit, and an extension capture circuit. , an extension detection circuit that detects dial pulses, a decoder that counts dial pulses using the dial detection output of the extension detection circuit and outputs them to a terminal corresponding to the dial number, and when the output of the decoder is output, the main unit and each child and amplifier operation signal sending means for transmitting an amplifier operating signal for activating the calling amplifier of the handset to the information line between the machines, and when the extension button of the handset is pressed, the output of the handset detecting circuit and the corresponding crosspoint thyristor is triggered by the thyristor control circuit, and the slave unit and the extension trunk are coupled;
Next, when the called handset number is dialed, the audio gate connecting the called handset and the extension trunk is opened by the decoder output, and the paging audio signal from the calling handset is transmitted to the called handset. An extension calling system in a button telephone device, characterized in that the call is made by being sent to a communication path of a handset, amplified by the amplifier in the handset, and emitted from its speaker. 2. The audio gate is composed of a series connection of a diode and a capacitor connected in parallel with the cross-point thyristor, and a connection point between the diode and the capacitor is connected to the decoder output via a resistor. , wherein the diode is turned on by the decoder output, and the calling audio signal is sent to the communication path of the handset via the diode and the capacitor. An extension calling method in the button telephone device according to item 1. 3. On the communication path connecting each handset and the main device, there is a handset detection circuit that monitors the call current through a transistor and outputs an output corresponding to the call current, and a cross point for connecting each handset and the extension trunk. an audio gate placed in parallel with the thyristor; a thyristor control circuit that turns on the crosspoint thyristor in response to the output of the handset detection circuit; An extension detection circuit that detects recovery, a decoder that counts dial pulses based on the dial detection output of the extension detection circuit and outputs them to a terminal corresponding to the dial number, and when the output of the decoder is output, there is a connection between the main unit and each slave unit. amplifier operation signal sending means for transmitting an amplifier operation signal for activating the calling amplifier of the slave unit to the information line of the slave unit, and when the extension button of the slave unit is pressed, the output of the slave unit detection circuit and the thyristor The control circuit triggers the corresponding crosspoint thyristor to couple the handset with the extension trunk, and then when the called handset number is dialed, the decoder output connects the called handset with the extension trunk. The audio gate connecting the handset opens, and the calling voice signal from the calling handset is sent to the communication path of the called handset, is amplified by the amplifier in the handset, and is radiated from its speaker to confirm the call. Further, the decoder output is applied to the thyristor control circuit at the same time as the voice gate is opened by the output of the decoder, and when the called telephone answers, the handset corresponding to the handset is By applying the output of the detection circuit to the thyristor control circuit, the cross-point thyristor connecting the responding handset and the extension trunk is triggered to form an extension communication path, and when the decoder output disappears, the voice gate 1. An extension calling system in a button telephone device, characterized in that the extension calling system in a button telephone device is configured such that when the amplifier operation signal is closed, the transmission of the amplifier operation signal is stopped. 4. The audio gate is configured to include a series connection of a diode and a capacitor connected in parallel with the crosspoint thyristor, and a connection point between the diode and the capacitor is connected to the decoder output via a resistor. and wherein the diode is turned on by the decoder output, and the calling audio signal is sent to the communication path of the handset via the diode and the capacitor. An extension calling method in the button telephone device according to scope 3.