JPH0342827B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a doorphone telephone switching device, and particularly to a doorphone telephone switching device that puts the central line on hold when there is a doorphone call during a telephone call, and releases the hold on the central telephone line when the doorphone call ends. Relates to doorbell telephone switching equipment.

[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 includes a call switching circuit 2, a telephone call circuit 3, a door intercom call interface 4, a central office line incoming door intercom ring detection circuit 5, a handset 6, and a door intercom handset 7. There is.

This operation will be explained below. Normally, the contact c of the call switching circuit 2 is in contact with the b contact, but when a central office line call arrives and the central office line incoming doorbell call detection circuit 5 detects this, the central office line incoming call is received regardless of whether or not there is a doorphone call. is given priority, and the contact c of the call switching circuit 2 remains held on the b contact side. When the handset 6 is picked up in order to respond to the central office line in this state, the central office line call is made via the telephone office lines L1 and L2, the call switching circuit 2, the telephone communication circuit 3, and the handset 6. Further, when the call button (not shown) of the door intercom handset 7 is pressed to make a door intercom call, the incoming door intercom call detection circuit 5 detects this and changes the contact c of the call switching circuit 2 to the a contact. bring into contact. When the handset 6 is picked up in order to answer the doorbell in this state, the doorbell call is made via the doorphone handset 7, the doorphone call interface 4, the call switching circuit 2, the telephone call circuit 3, and the handset 6. Further, when a doorbell call is received during a telephone conversation on the central office line, the telephone call detecting circuit 5 detects this and sounds a chime sound. In such a case, the switching of the contact c of the call switching circuit 2 from the B contact to the A 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 try again. The only option is to pick up the handset and make a doorbell call.

Further, a telephone device (not shown) as shown below is conventionally known. This type of telephone device is made up of at least two telephones A and B that can hold the central office line and make extension calls possible.

The above-mentioned telephones A and B consist of a push button switch that is operated to place the central office line on hold, a holding circuit that is set based on the operation of the push button switch and reset based on a hold release signal, and a set of this holding circuit. A station line holding resistor is inserted between the station lines under the condition, a ring tone generating circuit whose input terminal is connected to a push button switch and whose output terminal is connected to an amplifier, whose input terminal is connected to a holding circuit and output It includes a hold tone generation circuit whose 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.

Suppose that the person connected to telephone A (hereinafter referred to as person A) receives a call, and the caller designates the person connected to telephone B (hereinafter referred to as person B). Therefore, the push button switch of telephone A is pressed.

When the switch is pressed, the holding circuit is set. This holding circuit interposes a resistor between the station lines,
and activates the hold music 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 the caller can detect the hold state of the central office line by this hold tone signal.

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 generating circuit. As a result, a ring tone is emitted from the speaker provided in telephone B.

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 B to connect to the central office line. Release the hold.

That is, when a particular 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 in the Background Art] However, such conventional telephone devices with a doorbell function have a problem in handling that even if a doorbell call is received during a telephone call on a central office line, the telephone cannot be answered until after the telephone call on the central office line has ended. In addition, with conventional telephone devices, when canceling hold on a central line, it is necessary to pick up the handset and then press a switch to cancel hold on the central line, which poses operational difficulties in that it is easy to forget to cancel hold. are doing.

[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 prevent a door intercom call from occurring during a central telephone call. You can answer the doorbell without terminating the central line call, and then return to the central line call.Also, when placing the central line call on hold, you can place the central line call on hold with the AND condition of calling the doorbell and operating the central line hold switch. It is an object of the present invention to provide a door intercom telephone switching device which is easy to handle and operate, thereby avoiding unnecessary hold times.

[Summary of the Invention] In order to achieve this object, the door intercom telephone switching device of the present invention is formed of a changeover switch having two circuits and two contacts that switch in conjunction with each other, and a transmitter and receiver are connected to the contacts of each circuit. A call switching circuit with a door intercom handset connected to one contact of each circuit and a telephone office line connected to the other contact of each circuit, and one circuit one contact that is opened and closed between the telephone office line connected to the call switching circuit. a central office line holding circuit to which an open/close switch and a current limiting means are connected; a central office line holding circuit driving means for switching contacts of the central line holding circuit; a call switching circuit driving means for switching contacts of a call switching circuit; When a doorbell call is detected during a telephone call and the telephone hold switch is turned on, the central telephone hold circuit driving means is activated, and when the doorphone call ends and the telephone hold release switch is turned on, the telephone call is activated. a first switch element that stops the operation of the holding circuit drive means;
When a doorbell call is detected during a call on the local line and the switch for holding the local line is turned on, the call switching circuit driving means is activated, and when the door phone call ends and the switch for canceling the hold on the local line is turned on, the call is switched. and a second switch element for stopping the operation of the circuit driving means.

[Embodiments of the Invention] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIG. Door intercom telephone switching device 1 of the present invention
0 is a relay RY as a central line holding circuit driving means that constitutes a call switching circuit 2, a central line incoming door intercom ring detection circuit 5, a central line holding circuit 11, and a control circuit 12.
1. Relay RY as call switching circuit driving means
2. Transistor as the first switch element
Tr1, a transistor Tr2 as a second switch element, a local line hold switch SW1, a local line hold release switch SW2, and gates Q1 to Q4. The call switching circuit 2 is a two-circuit, two-contact switch CW 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 the contact a of the circuit via the door intercom communication interface 4, and the telephone office lines L1 and L2 are connected to the other contact b of each circuit. One end of the office line incoming door intercom ring detection circuit 5 is connected to the office line L.
1 and L2, the other end is connected to a door intercom handset, and detects an incoming call from a central office line or a door intercom call. The central line holding circuit 11 is connected to the call switching circuit 2.
A one-circuit, one-contact opening/closing switch SW, which is opened and closed between two telephone office lines connected to the same, and a resistor R1 as a current limiting means are connected.
The relay RY1 switches the contacts of the station line holding circuit 11. The relay RY2 switches the contacts of the call switching circuit 2. One end of the station line hold switch SW1 is connected to the relay RY1,
The other end is grounded. The switch SW2 for canceling the hold of the local line has one end connected to a transistor which will be described later.
It is connected to Tr2 and the other end is grounded. Transistor Tr1, which has relay RY1 connected to its collector, activates relay RY1 when there is a doorbell call during a telephone call and switches on switch SW1 for telephone hold, and when the doorphone call ends, the telephone call is canceled. When the switch SW2 is turned on, the operation of the relay RY1 is stopped. Relay RY2 to collector
The transistor Tr2 to which is connected is connected to the switch SW for holding the central office line when a doorbell call is received during a telephone call on the central office line.
When switch 1 is turned on, relay RY2 is activated, and when the intercom call ends and station line hold release switch SW2 is turned on, relay RY2 is activated.
This is to stop the operation of RY2. Gate Q
1 to Q4 are transistors according to the output of the central office line incoming door intercom ring detection circuit connected to the input terminal thereof.
It controls Tr1 or transistor Tr2. As shown in FIG. 1, the door intercom telephone switching device 10 constructed in this manner operates as follows.

First, when making a telephone call to a central office, press the switch.
Since the contact c of the HS is in contact with the b contact, the voltage Vcc is applied to each part of the control circuit 12. In this state, the output of the intercom call detecting circuit 5 exhibits a zero potential because the incoming call from the office line is detected. Therefore, the transistor Tr2 is in a non-conductive state because zero potential is applied to its base via the resistor R7, and the relay RY2 cannot be activated. Therefore, the contact c of the call switching circuit 2 is in contact with the b contact. On the other hand, the transistor Tr1 is in a non-conducting state because the input end 8 of the gate Q3 is at zero potential and the zero potential is applied to its base via the resistor R13, so that the relay RY1 cannot be activated. Therefore, the station line holding circuit 11 remains open.

At this time, if there is a doorbell call, the output of the incoming doorphone call detection circuit 5 detects the doorphone call and exhibits a positive potential, so a positive potential is applied to the input terminal 8 of the gate Q3 and the input terminal 12 of the gate Q4. be done.

When you try to answer the doorbell and press switch SW1 for holding the central line, the switch
Since the contact c of the HS is in contact with the b contact, a positive potential is applied to the input terminal 9 of the gate Q3, and the base of the transistor Tr1 becomes a positive potential. The transistor Tr1, which has become conductive, is connected to the relay RY.
1 is activated to close the station line holding circuit 11, and a resistor R1 is interposed between the station lines L1 and L2 to hold the station line. Further, a positive position which 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, since a positive potential is applied to the base of the transistor Tr2 via the resistor R7, the transistor Tr2 becomes conductive. So relay
RY2 is activated and the contact c of the call switching circuit 2 is
Doorphone calls can be made by touching the contacts.

Also, during a doorphone call, the output terminal 3 of the gate Q1 is connected to the input terminal 13 of the gate Q4.
Since the output terminals 4 of the terminals 2 and 2 are respectively connected to the input terminal 9 of the gate Q3, the gates Q1 to Q4 collectively form a holding circuit to maintain the central office line hold and intercom call. That is, this is because a positive potential is applied to the holding circuit and transistor Tr1 via the hook switch HS when the handset 6 is picked up. Therefore, when the handset 6 is placed in the standby position and the switch is turned, the holding circuit is released and the station line hold is automatically released.

If you want to maintain the central office line hold state, you can temporarily place the handset 6 in a predetermined position on the telephone (not shown), and you can keep the central office line on hold while using the telephone. You can let others know that.

In addition, if you want to end the doorphone call and return to the central office line call, all you have to do is press the central line hold release switch SW2 to turn off the transistor Tr2 and stop the operation of the relay RY2. The contact c of the switching circuit 2 is brought into contact with the b contact and connected to the station lines L1 and L2. Furthermore, when the station line holding release switch SW2 is pressed, the input terminal 8 of gate Q3 and the input terminal 12 of gate Q4 change from positive potential to zero potential, so that the holding circuit formed by gates Q1 to Q4 is released. be done. Then, the potential of the input terminal 8 of the gate Q3 becomes zero, and the gate Q
Since the output terminal 3 of 1 is at zero potential, the transistor
Tr1 becomes non-conductive after a delay of a time constant determined by resistor R14 and capacitor C1. As a result, the operation of relay RY1 is stopped and station line hold circuit 1
1 is released and the station line hold is released.

[Effects of the Invention] As is clear from the above embodiments, the door intercom telephone switching device of the present invention is formed by a switching switch having two circuits and two contacts that switch in conjunction with each other, and the contactor of each circuit has a transmission/reception switch. The switch is connected between a call switching circuit, in which the door intercom handset is connected to one contact of each circuit, and the telephone office line is connected to the other contact of each circuit, and the telephone office line connected to the call switching circuit. A central office line holding circuit to which a one-contact opening/closing switch and a current limiting means are connected; a central office line holding circuit driving means for switching the contacts of the central line holding circuit; and a call switching circuit drive for switching the contacts of the call switching circuit. and when a doorbell call is detected during a telephone call and the switch for telephone hold is turned on, the telephone hold circuit driving means is activated, and when the doorphone call is terminated and the switch for canceling telephone hold is turned on. a first switch element that stops the operation of the central line holding circuit driving means; By including a second switch element that stops the operation of the call switching circuit driving means when the switch for canceling the hold on the central office line is turned on after the call ends, even if a doorbell call occurs during a telephone call on the central office line, It is possible to answer the doorbell without terminating the line call and then return to the central line call.Also, when placing the central line call on hold, it is possible to put the central line on hold with the AND condition of calling the doorbell and operating the central line hold switch. Therefore, unnecessary holding can be avoided and handling and operation can be facilitated.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a door intercom telephone switching device according to the present invention, and FIG. 2 is a block diagram of a conventional telephone device with an intercom function. 2... Call switching circuit, 6... Handset, 7... Door phone handset, 10... Door phone phone switching device, 11
...Office line hold circuit, L1, L2...Telephone office line, RY
1...Relay (station line holding circuit driving means), RY2
...Relay (call switching circuit driving means), Tr1...
Transistor (first switch element), Tr2...
Transistor (second switch element), SW1...
...Switch for station line hold, SW2...Switch for release of station line hold, CW...Changing switch, c...Contact, a...Contact, b...Contact, SW...Open/close switch, R1...Current limit means.

Claims (1)

[Claims] 1 It is formed of a changeover switch CW with a two-circuit, two-contact configuration that switches in conjunction, with a transmitter 6 connected to the contact c of each circuit, and a door intercom handset 7 connected to one contact a of each circuit.
However, the telephone office lines L1 and L2 are connected to the other contact b of each circuit.
and a central office line hold circuit 11 to which a one-circuit, one-contact opening/closing switch SW and current limiting means R1 are connected, which are opened and closed between the telephone exchange circuit 2 connected to the telephone exchange circuit 2 and the central office line connected to the telephone exchange circuit. , a central office line holding circuit driving means RY1 for switching the contacts of the central office line holding circuit, a call switching circuit driving means RY2 for switching the contacts of the telephone call switching circuit, and a central office line holding circuit driving means RY2 for detecting a door intercom call during a central office line call; Line hold switch
A first switch that operates the central line holding circuit driving means when SW1 is switched 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 SW2 is turned on. A switch element Tr1 operates the call switching circuit drive means when a door intercom call is detected during a telephone call and the switch for telephone hold is turned on, and the switch element Tr1 operates to terminate the door telephone call and release the telephone hold. A door intercom telephone switching device comprising a second switch element Tr2 that stops the operation of the call switching circuit driving means when the switch is turned on.