JPS6294059A - Doorphone telephone switching device - Google Patents

Abstract

PURPOSE:To execute a doorphone response without terminating a central office line call even if a doorphone call is present during a central office line call by adding a central office line suspending circuit to a telephone set with a doorphone function. CONSTITUTION:At the time of a central office line call, the probe (c) of a hook switch HS comes into contact with a connection point (b), and a voltage VCC is impressed on a control circuit 12. In this state, the central office line suspending circuit 11 is opened as it is. If a doorphone call is present at this time, the output of a central office line incoming doorphone call detection circuit 5 detects the doorphone call to demonstrate a positive potential, and therefore a positive potential is impressed on the input terminals 8 and 12 of gates Q3 and Q4. When a central office line suspending switch SW1 is pressed in order to respond the doorphone call, a transistor Tr1 is energized to close the circuit 11, and a central office line is suspended by interposing a resistance R1 between central office lines L1 and L2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a door intercom telephone switching device, and in particular, when a door intercom call occurs during a call to a central office line, the telephone switch is placed on hold.

The present invention relates to an intercom telephone switching device that releases the central office line from hold when the intercom call ends.

[Technical Background of the Invention] A telephone device with a door intercom function as shown in FIG. 2 has been known. This type of telephone device 1 with a door intercom function is composed of a call switching circuit 2, a telephone mouth vJ3, an interface 4 for door intercom calls, an incoming intercom door intercom call detection circuit 5, a handset [3, 1], and a hair phone handset 7. ing.

This operation will be explained below. Normal 1 Call switching circuit 2
When the contact C is in contact with the B contact, is it at ft or is there an incoming call from the office line? When this is detected by the incoming doorbell call detection circuit 5, the incoming call from the office line is given priority regardless of whether or not there is a call from the doorbell. The contact T-c of the call switching circuit 2 remains held on the h contact side. In this state, answer the central line/receiver 6
When the telephone is picked up, a central office line call is made via the telephone office line L1 (L2), the call switching circuit 2, the telephone call circuit 3, and the handset 6. Further, when the call button (not shown) of the doorbell answering device 7 is pressed and the doorphone does not ring, the 1-station line incoming doorbell call detection circuit 5 detects this and connects the contact C of the call switching circuit 2 to the a contact. contact with. In this state, when the handset 6 is picked up to answer the doorbell, the doorbell handset 7, the doorphone call interface 4, the call switching circuit 2, the telephone call circuit 3. A doorbell call is made through the handset 6. Further, if there is a 1-A phone call during a call on the central office line, the 3-door phone call detection circuit 5 detects this and makes a chime sound. In such cases, call IJJ
Switching from the 1] contact of the contactor C of the switching circuit 2 to the 1 contact does not occur. Therefore, if you try to answer the doorbell while talking on a local line, you need to end the phone call, wait for the contact C of the call switching circuit 2 to switch from the B contact to the A contact, and then transmit/receive again. There is no other way than to make a doorbell call by picking up the device 6.

Further, a telephone device (not shown) as shown below is conventionally known. This type of telephone device is very popular because it allows extension calls to be made while holding the central office line.

It is formed by two or more telephones A and B.

The above-mentioned telephones A and B include a push-button switch that is operated to place one station line on hold, a holding circuit that is set based on the operation of this push-button switch, and a holding circuit that is reset based on a hold release signal, and this holding circuit. A station line hold resistor is inserted between the station lines when the circuit is set, a ring tone generation circuit whose input end is connected to the push button switch and whose output end is connected to the amplifier, and whose input end is connected to the holding circuit. It is equipped with a hold tone generation circuit whose output end is connected to a central office line, an amplifier and a speaker whose input end is connected to a ring tone generation circuit and whose output end is connected to a speaker.

Now, the person connected to telephone A (hereinafter referred to as person A) performs the incoming call operation, and the caller then calls the person connected to telephone B (hereinafter referred to as person A).
In this case, first, Person A will appoint TI! , the push button switch of stuffing machine A is pressed.

When the switch is pressed, the holding circuit is activated. This holding circuit has a resistor interposed between the station lines and operates a held tone generation circuit. As a result, the office line is placed in a closed circuit (on hold) state due to the resistance, and a music on hold signal is sent to the office line from the music on hold generation circuit. Note that this hold tone signal allows the caller to detect the hold state of the central office line.

On the other hand, at the same time as the push button switch is pressed, a ringing tone signal is sent out from the ringing tone generation circuit.

This causes a ringing tone to be emitted from a speaker installed on the side of the telephone.

Person B, who was called by this ring tone, makes an extension call with Person A through the communication circuit of telephones A and B, which are connected to each other via a line, and then presses the keypad of telephone Y3 to put the central office line on hold. Perform the release.

That is, when a specific key on the keypad is pressed, the holding circuit is reset. When the holding circuit is reset, the resistor is disconnected from the central office line, resulting in a state of release from hold, thereby allowing party B to talk to the caller.

[Problems with the Background Art] However, such conventional telephone devices with a doorbell function have a problem in handling that even if the doorbell is called during a telephone call to the central office, the doorbell cannot be answered until after the telephone call to the central office has ended. In addition, with conventional telephone equipment, when canceling hold on a central line, it is necessary to pick up the handset and then press a switch to release the hold on the central line, which is an operational problem that makes it easy to forget to release the hold on the central line. It has its drawbacks.

[Object of the invention] The present invention has been made in view of the above-mentioned problems, and
By adding a central line holding circuit and a control circuit to a telephone device with a door intercom function, it is possible to make a door intercom call during a central telephone call.
To provide a door intercom telephone switching device which is easy to handle and operate and allows a door intercom response to be made without terminating a local line call, and then returns to the local line call.

[5f! Summary] To achieve this object, the door intercom telephone switching device of the present invention is a switch having a two-circuit, two-contact configuration that switches in conjunction with each other. A call switching circuit in which 1-Ahon handset is connected to one contact of the circuit, and a telephone office line is connected to the other contact of each @ circuit, and 2.A phone call switching circuit is located between the two telephone office lines connected to the call switching circuit. A central line holding circuit to which a switch having a contact structure and a current limiting means are connected; a central line holding circuit driving means for switching the contacts of the central line holding circuit; and a central line holding circuit driving means for switching the contacts of the call switching circuit. If there is a doorbell call during a call to one office line and the office line holding switch is turned on, the office line holding circuit driving means is activated, and when the doorbell call ends and the office line is switched on. a first switch element that turns on the holding release switch and stops the operation of the central line holding circuit driving means; and when the central line holding switch is switched on when there is a doorbell call during a central line call; and a second switch element that operates the switching circuit driving means and stops the operation of the call switching circuit driving means when the intercom call ends and the station line hold release switch is turned on. This is what I did.

[Embodiments of the Invention] A preferred embodiment of the present invention will be described in detail below with reference to FIG. The door intercom telephone switching device 10 of the present invention includes a call switching circuit 21, a station line incoming door intercom call detection circuit 51, a station line hold circuit 11. The control circuit 12 includes a relay RYl as a central line holding circuit driving means, a relay RY2 as a call switching circuit driving means, and a transistor T' r L as a first switch element.

Transistor T r 2 as a second switch element,
It is formed by a switch SW1 for holding the local line, a switch SW2 for canceling the holding of the local line, and gates Q1 to Q4.

The call switching circuit 2 is a two-circuit, two-contact switch that switches in conjunction with each other, and a transmitter/receiver 6 is connected to the contact C of each circuit via the telephone call circuit 3.

A door intercom handset 7 is connected to one contact point a of each circuit via an intercom communication interface 4, and telephone office lines L1 and L2 are connected to the other contact point a of each circuit. One end of the office line incoming door intercom ring detection circuit 5 is connected to the office line L1,
The other end of L2 is connected to the door intercom handset 7, and is used to detect an incoming call from a central office line or a door intercom call. The return hold circuit 11 is connected to a switch having a one-circuit, one-contact configuration that is opened and closed between two telephone office lines connected to the call switching circuit 2, and a resistor R1 as a current limiting means. Relay RYI is used to switch the contacts of the 1-station line holding circuit 11. The relay RY2 switches the contacts of the call switching circuit 2. The station line hold switch SWI is
One end is connected to relay RYI, and the other end is grounded. The station line hold release switch SW2 has one end connected to a transistor Tr2, which will be described later, and the other end grounded. A transistor Tri, which has a relay RYI connected to its collector, operates the relay RYI when there is a doorbell call during a call on the local line and the central line holding switch SWl is turned on.

After the doorphone call ends, the central line hold release switch SW2
When switched on, the operation of relay RYI is stopped. Transistor 1r2, which has relay RY2 connected to its collector, activates relay RY2 when there is a doorbell call during a call on the central office line and turns on the switch SWl for holding the central office line, and the door intercom call is terminated and the telephone line is put on hold. When the release switch SW2 is turned on, the operation of the relay RY2 is stopped. Gates Q1 to Q4 are connected to transistors 1 to T according to the output of the central office line incoming door intercom ring detection circuit connected to their inputs.
r 1 or transistor T r 2. As shown in FIG. 1, the intercom telephone switching device 10 constructed in this manner operates as follows.

First, during a telephone conversation on the central office line, the contacts '-f-c of the hook switch 1-(S) are in contact with the b contacts, so that the voltage Vcc is applied to each part of the control circuit 12.

In this state, the output of the intercom call detection circuit 5 detects an incoming call from the office line, so it exhibits a zero potential. Therefore, the transistor Tr2 has a zero potential applied to its base via the resistor R7. It is in a non-conductive state and cannot operate relay RY2.

Therefore, the contact C of the call switching circuit 2 is in contact with the b contact. On the other hand, the transistor Trl has the input terminal (8) of the gate Q3 at zero potential and the resistor R1 at its base.
Since zero potential is applied through 3, it is in a non-conducting state, and relay RYI cannot be activated. Therefore, the station line holding circuit 11 remains open.

If there is a doorbell call at this time, the output of the incoming doorphone call detection circuit 5 detects the doorphone call and exhibits a positive potential, so the input terminal (8) of the gate 1-Q3 and the input terminal (8) of the gate 1-Q4 A positive potential is applied to 12).

When you press the central line hold switch SWI to answer the doorbell, hook switch l (contact Pc of S
Since it is in contact with the contact 1], a positive potential is applied to the input terminal (9) of the gate 1-Q3, and the base of the transistor Tri becomes a positive potential. The 1-transistor Tri, now in a conductive state, operates the relays Y and Yl to open the station line hold circuit 11.

Central line L1. A resistor R1 is interposed between L2 to hold the central office line. Further, a positive potential that appears after being delayed by a delay circuit having a time constant determined by the capacitor C1 and the resistor R14 is applied to the input terminal (13) of the gate Q4. Then, a positive potential is applied to the base of the transistor Tr2 via the resistor R7, so the transistor Tr2 becomes conductive1, and the relay RY2 is activated and the contact C of the call switching circuit 2 is brought into contact with the a contact. You can now make doorbell calls.

Also, during a doorbell call, the output terminal of gate Q1 (
3) is connected to the input terminal (13) of gate Q4, and the output terminals (4) of gates 1 to Q2 are connected to the input terminal (9) of gate Q3, respectively, so that gates Q1 to Q4 are held as a whole. This is because a positive potential is applied to the holding circuit and the helangistor Tri through the hook switch HS when the handset 6 is picked up. Then, when the handset 6 is placed in the standby position Wr and the hook switch is switched, the holding circuit is released and the station line hold is automatically released.

If you wish to maintain the 1-station line hold state, you can temporarily place the handset 6 in a predetermined position on the telephone (not shown) and use the telephone while maintaining the 1-station line hold state. You can let others know what's going on inside.

M for doorbell calls again! If you want to return to the central line call by talking, press the central line hold release switch SW2 to turn off the transistor Tr2 and switch the relay RY.
2, the contact f of the call switching circuit 2 can be stopped.
-c is brought into contact with the b contact and connected to the station lines L1 and L2. Also, when the station line hold release switch SW2 is pressed -1-, the input terminal (8) of gate Q3 and the input terminal (8) of gate Q1-Q4 are pressed.
12) changes from positive potential to zero potential -r:','T
'-When the holding circuit formed by gates Q1 to Q4 is released, the input terminals (8) of gates 1 to Q3 become zero potential, and the output terminal (3) of gates 1 to 1 is released. Since the voltage becomes zero potential, the transistor ``rrl'' becomes non-conductive after a delay of a time constant determined by the resistor R14 and the capacitor C1. As a result, the operation of relay RYI is stopped, the station line hold circuit 11 is opened, and the station line hold is released.

[Effects of the Invention] As is clear from the above embodiments, according to the door intercom telephone switching device of the present invention, the call switching circuit is a switch with a two-circuit, two-contact configuration that switches in conjunction with each other. The circuit is located between two telephone office lines and is connected by a switch with one circuit and one contact configuration and one stage of current limiter, and the office line holding circuit driving means switches the contacts of the office line holding circuit, and is used to switch one call. The circuit driving means switches the contacts of the call switching circuit, the first switch element activates or stops the operation of the central line hold circuit 1!2, and the second Since the switch element is configured to actuate or stop the operation of the call switching circuit driving means, even if a doorbell call is received during a call on one office line, the doorbell answer can be answered without terminating the call on the office line. 1. It has the effect of being easy to handle and operate.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a door intercom telephone switching device according to the present invention;
FIG. 2 shows a block diagram of a conventional telephone device with door intercom function. 2... Call switching circuit 6... Handset/receiver 7... Door intercom handset 10... Door intercom telephone switching device 11... Office line hold circuit Ll , L2...Telephone office line RYI...Relay (office line holding circuit driving means)
RY2...Relay (call switching circuit driving means)
Trl...Transistor (first switch element 7-) 1' r 2......1-Transistor (second switch element)

Claims (1)

[Claims] It is a switch with two circuits and two contacts that switch in tandem, with the handset connected to the contact of each circuit, the door intercom handset connected to one contact of each circuit, and the telephone office line connected to the other contact of each circuit. a central office line holding circuit connected to a connected call switching circuit, a one-circuit, one-contact switch that is opened and closed between two central office lines connected to the call switching circuit, and current limiting means;
A central line holding circuit driving means for switching the contacts of the central line holding circuit; a call switching circuit driving means for switching the contacts of the telephone call switching circuit; A first actuator that operates the central line holding circuit driving means when turned on, and stops the operation of the central line holding circuit driving means when the intercom call ends and the central line holding release switch is turned on. The switch element operates the call switching circuit driving means when a doorphone call is received during a telephone call and the switch for telephone hold is turned on, and when the doorphone call is terminated, the switch for canceling telephone hold is turned on. and a second switch element that stops the operation of the call switching circuit driving means when the call switching circuit is activated.