JPS6019877B2 - Extension call detection method for button telephone equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a button telephone device in which the number of wires of a connection cord is reduced in a button telephone device in which a preliminary unit is connected in a branch manner.

Conventionally, in this type of equipment, the central telephone line, internal telephone line, various control lines, telephone supply lines, etc. were connected independently.
For example, the number of D wires in the connection cord between the main unit and the handset is 2 x 2 for the office line, 2 x 2 for the office line control, and 2 x 2 for the office line control. At least 13 core wires are required, including two for extension calls, one for the extension control line, and two for the power supply line.Additionally, an individual extension calling line is required, so the connection cord becomes thicker. There was also a drawback that the connector was large.

In order to overcome these drawbacks, button telephone devices with a reduced number of core wires have been proposed, but since they serve both the central office line and the extension line, calls between the central office line and the extension line can be made independently. The disadvantage is that it cannot be done.

The present invention provides a branch connection type button telephone device in which the connection cord for the n-line office line is configured with 12 core wires, so that calls to the office line and internal calls can be made independent of each other with a minimum number of core wires. The present invention provides a method for detecting extension calls in a key telephone device that can be used to detect extension calls.

The present invention will be explained in detail below with reference to the drawings.

Note that although the embodiment presented here is a button telephone device for two central office lines, embodiments with a different number of central office lines can be easily configured by adding or subtracting the central office line circuit and two essential lines. be.

In the embodiment shown in FIG. 1, 1 is the main device, 2 is a station line circuit, 3 is an arrival detection circuit, 4 is a ringing tone generation circuit, 5 is a hold detection circuit, 6 is a multipipulator, and 7 is a high frequency Control signal generation circuit, 8 is a monitoring circuit, 9 is a counting circuit, 10' is an individual selection signal tone generation circuit, 11 is a timer circuit, L1, L
2, LI', L2' are central lines, A, R, day, K, K', ×
, Y is the relay, al, a2, a3 are the contacts of relay A, r
l, r2, r3 are contacts of relay R, r2', r3' are contacts of relay R (not shown), hl, h2, h3 are contacts of relay day, h3' is contact of relay day (not shown) ,xl
, x2 is the contact of relay X, yl is the contact of relay Y, B1
, B2 is the battery, 10E1, 10E2, 1E1, 1E2
is the power supply for powering the slave unit, TI is the transformer, Trl ~
Tr6 is a transistor, D1 and D2 are diodes, RI
~R5 is a resistor, CH is a choke coil, C0, CI~C
3 is a capacitor. In addition, Futagawa Mako machine, 21 is a telephone call circuit, 22 is an amplifier control circuit, 23 is a call amplifier circuit,
24 is a secret call circuit, 25 is an extension individual call receiving circuit, 26 is a signal selection circuit, LKI-1 to LKI-3, LK2-1 to L
K2-3 is the contact of the central office line button, HKI, HK2 is the contact of the hold button, So K is the contact of the exercise phone key, HS1, HS2 is the contact of the hook switch, Ds, Di are the dial contacts, A
P, PV are relays, atl, at2 are relay AP contacts, tvl, tv2 are relay PV contacts, SWI is a switch for stopping station calls, SW2 is a switch for stopping extension calls, REC
T is a double-wave rectifier, T2 and T20 are transformers, AMP is an amplifier, SP is a speaker, Tr20 to Tr23 are transistors, S20 and S21' are thyristors, LD1 and LD2
are light emitting diodes, blood 20 and blood 21 are Zener diodes, D20 to D26 are diodes, R20 to R27 are resistors, and C20, C21, and C22 are capacitors. Further, 30 is another handset connected in parallel with the handset 20, 41,
Reference numeral 41' denotes a central telephone line, and 42-1 and 42-2 denote extension telephone lines which also serve as power supplies to the slave units. Next, the operation of the circuit of this device will be explained.

(Call) When making a call to the central office line, when you lift the handset (not shown) of handset 20, the contact HSI of the hook switch is made, and when you press the central office line button again, the contacts LKI-1 and LKI- of the central office button are closed.
2 is switched, the loop of the office line communication line 41 with the main device 1 is closed through the communication circuit 21, and communication current is supplied from the battery BI in the main device 1 to the handset 20.

Relay A is inserted into this loop, and relay A is operated by the communication current, and the office line is captured by contact al. At the same time, a current is supplied from the battery B2 between the neutral point of the office line communication line 41 and the extension line 42-2 through the contact a2, and this current is supplied to the office line communication line 41 through the handset 201.
Resistor R20 connected between the sex point and extension 42-2
and the light-emitting diode LDI is turned on as an indicator lamp, and the same operation is performed in all connected slave units to indicate that the central office line is in use. (Response to incoming call) Next, the operation when receiving a call from the central office line will be explained.

When a calling signal from the station arrives on the station lines L1 and L2, the signal is guided to the station arrival detection circuit 3, which activates the relay R. The ringing signal is normally sent in an intermittent cycle of 1 second with signal and 2 seconds without signal, and while relay R is receiving the ringing signal, it performs the same intermittent operation of 1 second on and 2 seconds off, and the contact rl, current is intermittently supplied from the battery B2 to the neutral point of the central office line communication line 41, and the light emitting diode LDI of the handset 20 blinks in synchronization with the ringing signal, making it easy to see the incoming central line call. On the other hand, in the handset 20, between extensions 42-1 and 42-2,
A calling amplifier circuit 23 is connected to the amplifier control circuit 22 through a double-wave rectifier circuit RECT, a hook switch contact HS2, and a relay AP contact atl. Diode D22 that conducts current → Zener diode ZD20
→ Relay AP → Diode ○23 → Station call stop switch SWI] and [Extension call stop switch SW2 that conducts current when extension call line 42-2 has positive polarity → Diode D24 → Relay AP → Zener diode ZD2
1 → diode ○25]. In the standby state, the extension call line 42-1 and the extension call line 42
A voltage of 10 BI is applied between 1 and 2, but EI>
Relay AP emotional voltage > EI-Ena voltage Vzosha
......The voltage value is set to satisfy the relationship m, and the relay AP is not operating.

During the period when relay R is on due to a call signal from the central office line, transistor Trl is turned on by contact r2 to operate relay
The voltage of 2-1 is switched from 10EI to 10E2, and this +
The voltage value of E2 is E2 - voltage V2.

2o>Relay AP emotional voltage
・・・・・・・・・It has the relationship of {2}, and as a result, the IJ Ray AP of each connected slave device
operates, the contact atl is made, and the calling amplifier circuit 2
3 is in operation.

Also, contact r3 of relay R allows the ringing tone from the ringing tone generating circuit 4 to pass through the transformer TI to the extension telephone line 42-1.
The signal is superimposed on the signal and transmitted to each handset, and is applied from the transformer T20 of the calling amplifier circuit 23 of each handset to the calling amplifier AMP, where it is amplified and then amplified from the speaker SP.
When the called party answers the call, the central office line is acquired in the same manner as the above-mentioned operation for calling the central office line, and an indication that the central office line is in use is displayed.
Also, since the ringing signal stops, relay R, relay ×,
The relay AP is restored and the paging amplifier circuit 23 also returns to the standby state. Furthermore, in the handset that answers by picking up the handset, the ringing amplifier circuit 23 is completely disconnected by the hook switch HS2. (Secret talk) Next, the operation of the secret control will be explained.

The secret communication circuit 24 in the handset is connected to the extension communication line 42- through the double-wave rectifier RECT and the make contact of the hook switch HS2.
1,42-2, and is also connected to the neutral point of the extension telephone line 41 through the make contact LKI-3 of the office line button as a control input. The break contacts tvl and tv2 of the secret relay PV are connected in series to the communication circuit 21,
When the confidential message relay PV is turned on, the communication circuit 21 is configured to transmit the confidential message. first. When capturing a station line that is not in use, since the station line is not in use, no current is supplied to the neutral point of the station line communication line 41, and the station line button on the handset 20 is pressed. However, the transistor Tr20' of the confidential communication circuit 24 is in an off state. When the caller picks up the handset, the hook switch HS2
The contact on the make side of is made, and power is supplied to the private communication circuit 24 from the extension lines 42-1 and 42-2, but since the transistor Tr20 is off, the gate of the thyristor S20 is connected through the resistor R22 and the diode ○21. A trigger voltage is applied to , and thyristor S2 is turned on. Therefore, the transistor Tr21 is off, and the secret relay P
V does not operate, and when the station line button is pressed, its contact LKI
-1 and LKI-2 are switched, the communication loop of the communication circuit 21 is closed, and the central office line is captured. When the communication loop is opened, relay A is activated and current is supplied to the neutral point of central communication line 41, and transistor Tr20 of secret communication circuit 24 is turned on, but thyristor S2 is already in the on state. , so it continues to capture the central office line. Next, the operation of the confidential communication when trying to acquire a central office line that is already being used by another handset will be explained.

Since the office line is in use, a voltage is applied to the neutral point of the office line communication line 41. First, we will explain the case where you press the central office line button and then lift the handset.

When the central line button is pressed, contact LKI-3 of the central line button
The current supplied to the neutral point of the office line communication line 41 flows through the diode D20 and the resistor R21 to the base of the transistor Tr20, and the transistor Tr20 is in the on state. When the make contact of the hook switch HS2 is closed and power is connected to the secret circuit 24, no voltage is applied to the gate of the thyristor S20, the thyristor S20 is off, and the resistor R2
3. The base voltage is applied to the transistor Tr21 through R24, the transistor Tr21 is turned on, the privacy relay PV is activated, the break contacts tvl and tv2 are broken, and the communication circuit 21 is disconnected from the central communication line 41, and the communication circuit 21 is disconnected from the central communication line 41. Interruptions to the central office line are prohibited. Further, the case where the station line button is pressed after lifting the handset will be explained next.

In this case, when the handset is lifted, power is supplied to the confidential communication circuit 24 as described above, but the transistor Tr20
Since thyristor S20 is on and transistor Tr21 is off, secret relay PV is in a state of not operating, and when the station line button is pressed next, contact LKI-3 is turned off.
is made and the voltage appearing at the neutral point of the central line communication line 41 turns on the transistor Tr20, and at the same time it breaks only at the moment when the central line button is pressed, the contact k breaks, so the syristor switch S2 is turned off. Since the transistor Tr20 is on, the thyristor S20 continues to be off, and the transistor Tr21 is turned on, which activates the secret relay PV, and the communication circuit mount 21 is also disengaged, resulting in a secret message. (Holding) Next, we will explain the operation when putting the station line on hold.

On the office line in use, relay A operates, and current is supplied to the neutral point of the office line communication line 41 through contact a2, and the lamp current is supplied to the office line indicator lamp LDI of all slave units from battery B2 through resistor R2. is flowing, and in the handset in use, the transistor Tr20 of the confidential communication circuit 24 is in an on state. If the hold button is pressed here,
Contact HKI makes, and [break contact L of the station line button]
KI-3 → Diode 020 → Hold button contact HKI
→Resistor R25→Thyristor S20→Break bush dot K→
Through the double-wave rectifier RECT], a holding current flows from battery B2 through resistor R2 while the holding button is pressed, and the potential difference across resistor R2 increases. The hold detection circuit 5 is configured to detect that a hold current flows through the resistor R2, and when the hold current flows, the transistor T
r2 is turned on, the hold relay is operated, the contact hl is made, and a straight line loop of the station line is formed by the resistor RI.
Next, when the hold button is released, the call circuit 21 of the handset is disconnected by the contacts LKI-1 and LK1-2 of the central line button. and relay A is restored. Furthermore, since the pending relay date is restored slowly and slowly by the capacitor CI, the pending relay date is self-held by the contacts a3 and h2. The relay K is connected to the transistor Tr3 by the contact h3, and the relay K is turned on and off by the multipipulator 6 which oscillates at about 1'2 Hz, and the contact KI connects the relay K to the transistor Tr3. Current is intermittently supplied from the battery B2 to the sex point, and the station line indicator lamp LDI of each handset flashes to indicate the pending state. Next, when canceling the hold and re-answering, the handset of the handset is lifted and the central office line button is pressed to acquire the central office line. Note that while the indicator lamp is on, current is supplied to the neutral point of the central office line 41, resulting in the confidential conversation state described above, but when on hold, current is supplied to the neutral point intermittently at a cycle of approximately 1/2 Hz. Therefore, during the period when the connection of this current is cut off, the transistor Tr20 of the privacy circuit 24 is turned off, and in order to turn on the thyristor S20, the privacy relay P is turned off.
V is restored, the communication loop is opened, relay A is activated, and the central office line is reacquired. When relay A operates, contact a3
The self-hold on the relay date is released and the contact hl is restored.
breaks, the holding loop caused by resistor RI is removed, and .
A local line call is established. (Extension) Next, we will explain the operation when making an extension call.

If you lift the handset without pressing the central line button,
The telephone call circuit 21 has a break contact LKI-1 of the office line button,
It is connected to extension communication lines 42-1 and 42-2 through LK2-1, LKI-2, and LK2-2, and a communication current is supplied to the communication circuit 21. Further, a capacitor C20 connected in series with the break contact HK2 of the hold button is also connected to the extension communication lines 42-1 and 42-2. The capacitor C20 has a sufficiently high impedance for signals in the audio frequency band, and has a capacitance value that provides low impedance for high frequency control signals, which will be described later. On the other hand, a high-frequency control signal is always superimposed on the extension communication lines 42-1 and 42-2 from a high-frequency control signal generation circuit 7 composed of a multipipulator, etc., and this control signal is sent to the monitoring circuit 8 as a signal. size is being monitored. When no handset is using an extension, the load of the high-frequency control signal is light, the magnitude of the high-frequency control signal applied to the monitoring circuit 8 is greater than the detection level of the monitoring circuit 8, and the output of the monitoring circuit 8 is , an AC signal switched by a high frequency control signal is output, and the output signal is rectified and smoothed by a diode DI and a capacitor C2, turning on the transistor Tr4 and turning off the transistor Tr5. Now, when one handset is connected to use the extension line as described above, the capacitor C20 is connected as a load of the high frequency control signal generation circuit 7, and since the load is low impedance, it is applied to the monitoring circuit 8. The magnitude of the signal is divided by the resistor B3 and the load capacitor C201 and becomes smaller, and becomes less than the detection level of the monitoring circuit 8, and no alternating current signal is generated at the output of the monitoring circuit 8. Transistor Tr4 is turned off, transistor Tr5 is turned on, and relay Y operates. Contact yl of relay Y causes a voltage of -EI to be applied to extension line 42-1, and current flows through light emitting diode LD2 of resistor R26 in the handset, lighting up the extension indicator lamp, and through diode D26. Power is supplied to the extension individual call receiving circuit 25, and base current flows to the transistor Tr20 through [resistance R27 → break contact LK2-3 of the office line button, LKI-3 → diode D20 → resistor R21], and the transistor Tr20 is turned on. This means that other handsets than those who made the call will be in a confidential state where they will not be able to capture the extension. Next, in order to call an extension individually, when the extension caller dials the individual extension number, the shaft contact Ds of the dial is made during dialing, becomes a load instead of the capacitor C20, and the dial contact Di corresponds to the number of dials. This load is then intermittent.

Due to the intermittent load, the level of the high frequency control signal applied to the monitoring circuit 8 changes, and a dial pulse is generated at the output of the monitoring circuit 8 due to the intermittent alternating current signal, and the resistance R6 and diode D
2. The pulse is corrected to a complete dial pulse by a rectification and time constant circuit including a capacitor C3 and a resistor R7, and is counted by a counting circuit 9. On the other hand, the transistors Tr4 and Tr5 that detect the extension state do not operate when the AC signal is interrupted by the dial due to the time constant of the circuit of resistor R4, diode D1, capacitor C2, and resistor R5, and maintain the extension state. There is. By the output of the counting circuit 9,
A signal tone having a frequency corresponding to the number of dials is generated from the individual selection signal tone generation circuit 10, superimposed on the extension communication line 42-1 through the transformer TI, and sent to the handset. In each handset, a signal selection circuit 2 is installed in the extension individual call reception circuit 25.
6 is provided, and when the received signal frequency matches the set frequency, an output is generated from the signal selection circuit 26,
Thyristor S21 is turned on, transistor Tr22 is turned off, transistor Tr23 is turned on, the Jenner diode D21 is short-circuited, and EI is set to the condition of the expression {1-, so when the Jenner diode ZD21 is short-circuited. The relay AP operates, the call amplifier circuit 23 is activated by the contact apl, and the caller's voice is transmitted from the call circuit 21 of the calling handset to the extension call lines 42-1, 42-.
2, and also extension lines 42-1 and 42-2.
The signal is amplified by the above-mentioned paging amplifier circuit 23 connected to the speaker SP, and is amplified by the speaker SP. In addition, in the handset that has received a call, the relay AP is operating, and the base current flowing to the transistor Tr20 of the privacy circuit 24 is bypassed by the contact ap2, so that the privacy is released and the call can be answered. . Therefore, when the called party picks up the handset, the telephone call circuit 21 is connected to the extension telephone lines 42--, 42-2 in parallel with the telephone circuit 21 of the handset that has made the call, allowing an extension telephone call to be made. In addition, the calling amplifier circuit 2 of the called handset
3 is disconnected by the contact HS2 of the hook switch, and the operation is stopped. Next, a case where simultaneous calling is performed using an extension will be explained. The general paging operation is the same as the above-described individual paging up to the capture of the extension line, and when the extension line is captured, the transistor Tr4 is turned on and the transistor Tr5 is turned off. Next, when you press the simultaneous call button that also serves as the hold button, the break contact HK2 breaks, the load capacitor C20 is activated, and the output of the monitoring circuit 8 becomes the same state as when no handset is connected. The transistor Tr4 is turned on and the transistor Tr5 is turned off. When this transistor Tr4 returns from off to on, the collector voltage changes from a high level to a low level, so that a timer circuit 18 such as a monostable multi-circuit whose operating time is set to about 5 seconds is activated, and the transistor Tr6 is turned on, during which time relays X and Y operate, and a voltage of -E2 is applied to extension line 42-1. The voltage value of E2 is set to the condition of formula (2) as described for the calling operation from the central office line, and in the amplifier control circuit 22 of all slave units, the voltage value of diode D24, relay AP, and Zener diode ZD2 1 , a current flows to the relay AP through the diode D25, the relay AP operates, and the paging amplifier circuits 23 of all slave units operate, thereby performing simultaneous paging. In the embodiment shown in FIG. 1, the transformer T2 is a coupling circuit that forms an intuition loop for the office lines L1, L2 and the office line communication line 41, separates them from each other in terms of direct current, and further couples them to each other in terms of alternating current. Although it is used as
If it has such a function, it can be used as a coupling circuit, so the coupling circuit shown in FIG. 2a can be modified as shown in FIG. 2b.

In this example, an intuition loop is formed by the choke coil CHI for the office lines L1 and L2, and by the relay A and the battery BI for the office line communication line 41, respectively.
Further, mutual direct current separation and alternating current coupling are performed by capacitors CI1 and C12. As described above, according to the present invention, each slave unit 20, 30 is connected to the extension line 42-1, 42-2, which is also used for power supply to each slave unit, and the central office line 41 in the device. In the branch-connected button telephone device, the main device includes a signal generator 7 for superimposing a high-frequency signal on the central communication line, and a monitoring circuit 8 for separating the voltage value of the high-frequency signal, The machine includes a connection means KS for connecting an element C20 exhibiting low impedance to the high frequency signal to the extension communication line when the extension is used.
I, it is possible to realize an extension call detection method in a key telephone system configured to detect a call to the extension call line by the monitoring circuit.

The above explanation is for the entire device, but the present invention is characterized by using a high-frequency signal to detect calls from an extension line, connecting an element that exhibits low impedance to this high-frequency signal when using the extension line, This detects a change in the voltage value of the high frequency signal and detects an extension call.

Conventional extension call detection was performed by detecting the DC current value of the extension, and the DC voltage superimposed on the extension could not be used as a power source for the handset circuit. However, according to the present invention, , it becomes possible to freely use the DC voltage superimposed on the extension line as a power source for the slave unit, and the extension line can be shared with the power supply line that was previously provided to independently supply power to the slave unit. This has the effect of reducing the number of cores in the connection cord of the button telephone device.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the invention, and FIG. 2 is a circuit diagram showing a partially modified example of the invention. Figure outside 2 [o] Figure 2 (b) Figure po

Claims (1)

[Claims] 1. In a button telephone device in which each handset is branch-connected to an extension line that is also used to supply power to each handset and a central office line inside the device, a high-frequency signal is superimposed on the extension line in the main unit. and a monitoring circuit that separates the voltage value of the high-frequency signal, and each slave unit has an element that exhibits low impedance to the high-frequency signal when the extension line is used, connected to the extension line. 1. A method for detecting an extension call in a button telephone device, characterized in that the monitoring circuit is configured to detect a call to the extension call line.