JPS6019878B2 - Individual extension calling 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 for branch-connecting handsets.

Conventionally, in this type of equipment, the central telephone line, internal telephone line, various control lines, power supply lines, etc. are connected independently.
Taking a button telephone device for two central office lines as an example, the number of fibers in the connection cord between the main unit and the slave unit is 2x2 for central line calls, 2x2 for central 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 the central telephone line and the extension telephone line are both used, the central telephone line and the extension telephone line are independent. 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 office line is constructed with 12 core wires, so that telephone calls between the central office line and internal telephone calls can be made with a minimum number of core wires. This provides an extension individual calling system in a key telephone device that can be called independently.

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

Although the embodiment shown here is a button telephone device for two office lines, embodiments with a different number of office lines can be easily constructed by adding or subtracting the office line circuit and two core wires. be.

In the embodiment shown in FIG. 1, 1 is a main loader, 2 and 2' are station line circuits, 3 is an arrival detection circuit, 4 is a ringing tone generation circuit, 5 is a hold detection circuit, 6 is a multipipulator, 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,
L2, LI', L2' are central lines, A, R, day, K, K',
X, Y are relays, al, a2, a3 are contacts of relay A,
rl, 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 relay H' (not shown) , KI is the contact of relay K, X1, ×2 is the contact of relay power supply, TI is a transformer, Trl to Tr6 are transistors,
D1 and D2 are diodes, RI to R5 are resistors, CH is a choke coil, and C0 and CI to C3 are capacitors.
In addition, 20 is a handset, 21 is a communication circuit, 22 is an amplifier control circuit, 23 is a calling amplifier circuit, 24 is a confidential circuit, 25 is an extension individual call receiving circuit, 26 is a signal selection circuit, and LKI-1
~LKI-3, LK2-1 ~ LK2-3 are the contacts of the office line button, HK1, HK2 are the contacts of the hold button, SoK is the contact of the interlocking electric key, HS1, HS2 are the contacts of the hook switch, Ds, Di are the contacts of the hook switch. Dial contact, AP, PV are relays, a
tl, 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, RECT is a double wave rectifier, T2,
T20 is a transformer, AMP is an amplifier, SP is speaker power,
Tr20 to Tr23 are transistors, S20 and S21 are thyristors, LD1 and LD2 are light emitting diodes, and ZD2
0, ZD2 1 is a Zener diode, D20~D2
6 is a diode, R20 to R27 are resistors, C20, C2
1, C22 is a capacitor. Also, 30 is the slave unit 20
The other handsets connected in parallel with the handset, 41, 41' are central communication lines, and 42--, 42-2 are extension communication lines which also serve to supply power to the handsets. Next, the operation of the circuit of this device will be explained.

(Call) When you raise the handset (not shown) of handset 20 when making a call to the local line, the contact HSI of the hook switch is made, and when you press the local line button again, the contacts LKI-1, LKI- of the local line button are closed.
2 is switched, the loop of the office line communication line 41 between the main device 1 and the main device 1 is opened 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 passed through the handset 20' to the neutral point of the office line communication line 41 and the extension line 42-2. The current flows through the resistor R20 and the light emitting diode LDI connected between the extension line 42-2, the light emitting diode LDI as an indicator lamp lights up, and all the connected slave units operate in the same way, indicating that the central office line is in use. will be carried out. (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, and the relay R is activated. The ringing signal is normally sent in an intermittent cycle of 1 second with signal and 2 seconds without code, 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 Due to rl, the central telephone communication line 41 is in a state where current is intermittently supplied from battery B2 to the neutral point,
The light emitting diode LDI of the handset 20 flashes in synchronization with the calling signal, providing a visible indication of the arrival of the central office line call. On the other hand, between extensions 42-1 and 42-2, in the handset 20, the amplifier control circuit 22, the double-wave rectifier circuit RECT, the hook male switch contact HS2, and the relay AP contact atl
The calling amplifier circuit 23 is connected through the amplifier control circuit 22.
D20 → relay AP → diode D23 → station call stop switch SWI] and the extension call stop switch S that conducts current when the extension call line 42-2 has positive polarity.
The route is W2→diode D24→relay AP→Zener diode ZD21→diode D25]. In the standby state, a voltage of 10 EI is applied between the extension telephone line 42-1 and the extension telephone line 42-2, but EI>Relay AP voltage>EI-Ena voltage V
20...The voltage value that satisfies the relationship [1} is set, 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 VzD2o > relay A
P's emotional voltage...
... has the relationship {2}, whereby the IJ relay AP of each connected handset operates, the contact atl is made, and the calling amplifier circuit 23 becomes operational.

In addition, the ringing tone from the ringing tone generation circuit 4 is transmitted through the transformer TI to the extension telephone line 42-1 by the contact r3 of the Lillay R.
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 calling signal stops, relay R, relay
The relay AP is restored and the paging amplifier circuit 23 also returns to the standby state. Further, in the handset that answers the call 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 private communication circuit 24 in the handset is connected to the extension communication line 42- through the double-wave rectifier RECT and the closing contact of the hook switch HS2.
2, 42-2, and is also connected to the neutral point of the office line communication line 41 through the make contact LKI-3 of the office line button as a control input. The break contacts W1 and tv2 of the secret relay PV are connected in series with the communication circuit 211,
When the confidential message relay PV is turned on, the communication circuit 21 is disconnected and the confidential message is configured. First, when capturing a station line that is in use, since the station line is not in use, no current is supplied to the neutral cutout of the station line communication line 41, and the station line button on the handset 20 is pressed. The transistor Tr20 of the confidential communication circuit 24 is in an OFF state even if the communication is switched off. When the caller picks up the handset, the hook switch HS2 closes.
The contact on the contact side is made, and the extension communication line 42 is
Power is supplied from -1,42-2, but since transistor Tr20 is off, resistor R22 and diode D
A trigger voltage is applied to the gate of thyristor S20 through 21, and thyristor S20 is turned on. Therefore, the transistor Tr21 is off, the secret relay PV does not operate, and when the office line button is pressed, its contacts LKI-1,
LKI-2 is switched, the call loop of the call circuit 21 is closed, and the central office line is captured. When the call loop is closed, relay A operates, current is supplied to the neutral point of central office line 41, and transistor Tr20 of secret call circuit 24 is turned on, but sirist S20 is already in the on state. Because there is
Continue to capture the station line as it is. 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, the central line button contacts LK1-3
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.Then, when the handset is lifted, the hook switch is activated. When the make contact of HP2 is made and power is supplied to the secret circuit 241, no voltage is applied to the gate of thyristor S20, and even thyristor S201 is off, and resistor R2
3. The base voltage is applied to the transistor Tr21 through R2-4, the transistor Tr21 is turned on, the secret relay PV is activated, the break contacts W1 and tv2 are broken, and the communication circuit 21 is disconnected from the central communication line 41. Interruptions to the station line in use 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
is off, the secret relay PV is in a state of not operating due to the on of the thyristor S20 and the off of the transistor Tr21, and when the central line button is pressed next, the 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. At the same time, the contact Tr20, which breaks only at the moment the central line button is pressed, breaks, so the thyristor S2 remains in the off state. After the recovery, the transistor Tr20 is on, so the thyristor S
20 continues to be off, and when the transistor Tr21 is turned on, the confidential communication relay PV is operated, and the communication circuit 21 is also disconnected, resulting in a confidential communication. (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 from point 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 being played, and the thyristor S20 of the confidential communication circuit 24 is in the on state in the handset in use. If the hold button is pressed here, contact H
KI makes the break contact LKI- of the station line button.
While the hold button is pressed, the hold current flows from the battery B2 through the resistor R2, and the hold current flows through the resistor R2 while the hold button is pressed. When the potential difference across 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 Tr2
is turned on, the hold relay is operated, the coin point HL is made, and a direct current loop of the station line is formed by the resistor RI. Next, when the hold button is released, the telephone line button is also restored at the same time as the hold button is restored, and the communication circuit 21 of the handset is disconnected by the contact LKI-2 of the central line button. Relay A is restored. Further, since the hold relay date is restored slowly and slowly by the capacitor CI, the hold relay date is self-maintained by contact a3 and contact h2. Relay K is connected to transistor Tr3 through contact h3, and relay K is turned on by multipipulator 6 which is oscillating at approximately 1/2 Hz. An intermittent off operation is performed, and current is intermittently supplied from the battery B2 to the neutral point of the office line communication line 41 by the contact KI, and the office line indicator lamp LDI of each handset flashes to indicate the hold 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 supply of this current is cut off, the transistor Tr20 of the confidential communication circuit 24 is turned off.
In order to turn on thyristor S20, secret relay P
V recovers and uses secret relay P to turn on S20.
V is restored, the call loop is closed, relay A is activated, the central office line is recaptured, and when relay A is activated, the self-holding of the relay date is removed by coin point a3 and the relay is restored, and ``contact hl breaks.'' Then, the holding loop caused by the resistor RI is broken, and the state becomes a central office line call.(Extension line) Next, the operation during an extension line call will be explained.

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 the 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 HKK2 of the hold button is also connected to the extension communication lines 42-1 and 42-2. The capacitor C20G 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 pigeon circuit 7 composed of a multi-pipe rake, etc., and this control signal is also superimposed by a monitoring circuit 8. Signal magnitude is 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 slave unit is connected to use the extension 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 added to the monitoring circuit 18. The magnitude of the signal is reduced by being divided by the resistor B3 and the load by the capacitor C20, and becomes below the detection level of the monitoring circuit 8, and no AC signal is generated at the output of the monitoring circuit 8, and the transistor Tr4 is turned off. In this state, the transistor Tr5 is turned on, and the relay Y operates. A voltage of -EI is applied to the extension line 42-1 by the contact yl of the relay Y, and current flows through the resistor R26 and the light emitting diode LD2 in the slave unit, lighting up the extension indicator lamp, and also passing the extension line through the diode D26. Power is supplied to the individual call receiving circuit 25, and a base current flows through the transistor Tr20' through [resistance R27 → break point LK2-3 of the central line button, LKI-3 → diode D20 → resistor R21], and the transistor Tr20' When the call is turned on, the extension becomes confidential and cannot be picked up by handsets other than the one that made the call. 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 the rectification and time constant circuit formed by the capacitor C3 and resistor R7, and then counted by the 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 generating circuit 10, superimposed on the extension line 42-11 through the transformer TI, and sent to the handset.
In each handset, a signal selection circuit 26 is provided in the extension individual call reception circuit 25, and when the received signal tone and the set frequency match, the signal selection circuit 26 generates an output and turns on the thyristor S21. , the transistor Tr22 is turned off, the transistor Tr23 is turned on, the Zener diode ZD21 is short-circuited, and since BI is set to the condition of the expression {1-, the relay AP is set as soon as the Zener diode ZD21 is short-circuited. Then, the call amplifier circuit 23 is activated by the contact apl, and the caller's voice is sent from the call circuit 21 of the calling handset to the extension call lines 42-1 and 42-2. 42-1, 42-2
The signal is amplified by the above-mentioned paging amplifier circuit 23 connected to and amplified by the speaker SP. In addition, in the handset receiving the call, the relay AP is operating, and the base current flowing through the transistor Tr20 of the privacy circuit 24 is bypassed by the contact aP2, so that the privacy is released and the handset can respond to the call. Therefore, when the called party picks up the handset, the telephone call circuit 21 is connected to the extension telephone lines 42-1 and 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. Further, the calling amplifier circuit 23 of the called handset is disconnected by the contact HS2 of the hook switch and stops operating. Next, a case will be described in which simultaneous calling is performed using an extension.

The operation of simultaneous calling is the same as the above-mentioned individual calling until the extension line is captured, and when the extension line is captured, the transistor Tr
4 is on. Transistor Tr5 is off. Next, when the simultaneous call button that also serves as the hold button is pressed, the break contact HK2 breaks, the load capacitor C20 is disconnected, 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. Roller transistor Tr4
When the transistor Tr6 changes from off to on, the collector voltage changes from a high level to a low level, which causes a timer circuit 18 such as a monostable multi-circuit whose operating time is set to approximately 5 seconds to operate, turning on the transistor Tr6. , during which relays X and Y operate, and a voltage of -E2 is applied to extension line 42-1. The voltage value of this E2 is
As mentioned above regarding the operation of calling from the central office line, the conditions of formula {2) are set, and the amplifier control circuit 22 of all slave units
At this point, current flows to the relay AP through the diode D24, the relay AP, the Zener diode ZD21, and the diode D25, the relay AP operates, and the calling amplifier circuits 23 of all slave units operate, thereby performing simultaneous calling. In the embodiment of FIG. 1, the transformer T2 is connected to the central line L1,
It is used as a coupling circuit that forms a DC loop for L2 and the central communication line 41, separates them from each other in terms of DC, and connects them to each other in terms of AC. Since it can be used as this coupling circuit, this coupling circuit shown in Fig. 2a can also be modified as shown in Fig. 2b.In this example, the choke coil CH is used for the station lines L1 and L2. Office line telephone line 41
A DC loop is formed by relay A and relay BI, respectively, and capacitors CI1 and C12
Mutual direct current separation and alternating current coupling are performed.
As described above, according to the present invention, each handset 20, 30 is branched to the extension communication line 42-1, 42-2, which is also used for power supply to each handset, and the office line communication line 41 within the device. In the connected button telephone device, the main pupil is provided with a signal generator 7 for superimposing a high frequency signal on the extension communication line, and a monitoring circuit 8 for identifying the voltage value of the high frequency signal, and a monitor circuit 8 for identifying the voltage value of the high frequency signal. is equipped with dial contact means Ds, Di for intermittently connecting the load exhibiting low impedance with respect to the high frequency to the extension telephone line by dial operation; and an individual selection signal sound generation circuit 10 for generating an individual selection signal sound corresponding to the counted number of pulses and superimposing it on the extension communication line, The handset includes signal tone extraction means C21, CH21, which extracts the individually selected signal tone from the extension line.
C22, CH22, 25, a signal selection circuit 26 that outputs an output when the individually selected signal tone from the signal tone extraction means is assigned to the slave unit, and a signal selection circuit 26 that outputs an output when the individually selected signal tone from the signal tone extraction means is assigned to the slave unit It is possible to realize an extension individual calling system in a key telephone device equipped with control means 22 and 23 that enable the telephone to respond to an individual call.

The above explanation is for the entire device, but the feature of the present invention is that a high frequency signal is used to detect a call from an extension line, and when an extension line is used, an element exhibiting low impedance to this high frequency signal is connected. This detects a change in the voltage value of the high-frequency signal and detects an extension call, and utilizes the fact that the output is intermittent with a dial operation to individually call the extension.

Previously, extension calls were detected by detecting the direct current value of the extension, and the direct current voltage superimposed on the extension could not be used as a power source for the cordless handset circuit. For example, 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 units. This has the effect of reducing the number of cords of 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. Juice 2 figure [0) Sai 2 figure (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 for identifying the voltage value of the high-frequency signal, and each slave unit is provided with a load that exhibits low impedance to the high-frequency signal and is connected to the extension telephone line by a dial operation. The main device further includes a counting means for counting pulses generated at the output of the monitoring circuit due to the intermittent connection, and generating an individual selection signal sound corresponding to the counted number of pulses. and an individual selection signal tone generating circuit for superimposing the individual selection signal tone on the extension communication line, and each handset includes a signal tone extraction means for extracting the individual selection signal tone from the extension communication line; a signal selection circuit that outputs an output when the individual selection signal tone from the slave unit is assigned to the slave unit; and a control means that puts the slave unit in a state capable of responding to the individual call by the output of the signal selection circuit. An extension individual calling method for key telephone devices equipped with