JPS60250755A - Two-wire type answering buzzer device - Google Patents

Abstract

PURPOSE:To speak through at least two telephone lines by applying impedance between the lines by depressing a call switch to change inter-line voltage, detecting the voltage change and turning a ringing tone generating circuit to a voltage source to drive a speaker. CONSTITUTION:When a call is generated from a central telephone office, a 16Hz AC signal is superposed to the telephone lines L1, L2 at a DC level. Call generating circuits Ga, in respective answering buzzers A1, A2 generate ringing tones by any one of AC and DC. Receiving the 16Hz AC singal, the call generating circuits Ga drive respective speakers Pa. If a telephone receiver is hooked off in one telephone set T1, a call signal from the office is stopped and an inter-line voltage is set up only to a fixed DC level. When an affair switch Sw of an opposite side is closed, the inter-line voltage is dropped, voltage change detecting circuits D in both the answering buzzers A1, A2 detect the voltage drop, turn switching contacts from aa to bb and generate call tones.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an answering buzzer device connected in parallel to each telephone in order to transmit and receive an answering buzzer sound signal between a plurality of telephones connected to a telephone line. It is related to.

[Background Art 1] In general, in parent-child type telephones, when it is necessary to pick up the handset of one telephone to answer a call and transfer the call to another telephone depending on the other party's business, conventionally, as shown in Fig. 2, The response buzzer signal was transmitted using the preceding wiring, that is, the vacant line. In the same figure, response buzzer devices A, A2
are a ringing tone generating circuit Ga and a response buzzer generating circuit Gb.
The telephone line L2 and the idle line L3L are respectively composed of the telephone line L2 and the idle line L3L.

Signals are sent using the . Telephone T
, T2 connects to the telephone line L via 2 to the telephone line L.
+ L 2 is connected to the telephone line L + L
When a ringing signal voltage from the telephone office is applied between 2 and 2, the speaker Pa of the ringing tone generation circuit Ga sounds. now .

If you pick up the handset of telephone T1 and want to transfer the call to telephone T2 in the next room while it is busy, press the call switch 5Ill.
Press. Then, a response buzzer sound signal is sent out from the response buzzer sound generation circuit Gb, and the speaker pb of the response buzzer device A2 in the next room is made to sound. When the handset of telephone T is picked up and the handset of telephone T is taken down, telephone T2
and a conversation with the other party begins. If there are three or more telephones, the speakers of all answering buzzer devices will sound, so it is only necessary to determine the signal for the buzzer sound. Furthermore, C,
C2 is a DC blocking capacitor.

In the conventional device as described above, telephone lines L, L2
In addition, two wires L3L are required for transmitting the response buzzer sound signal, and there is a problem in that if there are no free wires, a new wire must be added.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to provide a system that can add an answering buzzer function using only two existing wires without impairing telephone calls. We provide wire response buzzer devices.

[Disclosure of the Invention 1 The two-wire response buzzer device of the present invention has a ring tone generation circuit that generates a ring tone upon detecting the application of a voltage, which is connected to a telephone line and a voltage source via a switching contact. At the same time, it is constructed by connecting to the telephone line a voltage change detection circuit that detects a change in line voltage and operates the switching contact described in 1. By pressing the ring switch on one telephone to lower the line voltage, the voltage change detection circuit operates the switching contact on the other telephone, connecting the voltage source and the ring tone generation circuit. In this way, the ringing tone generating circuit is used as a response buzzer.

The present invention will be described in detail below based on the embodiment shown in FIG. In the figure, a telephone T1T2 is connected to the telephone line L2, and response buzzer devices A and A2 are provided for each telephone.
, the ringing tone generating circuit Ga is switched between the switching contacts aa and b.
a voltage change detection circuit which is connected to the telephone line L 1L 2 and the voltage source E through the telephone lines L 1 L 2 and the voltage generation source E, respectively, and which operates a switching contact when detecting that the line voltage has decreased below a certain level; and a call switch 5I11. An impedance R, which is applied between the lines and reduces the line voltage by suppressing the voltage, is connected to the telephone line and L2.

Next, the operation of the circuit shown in FIG. 1 will be explained. When there is a call from the telephone office, a 16 Hz AC signal is superimposed on the DC level on the telephone line L2.

The ringing tone generation circuit Ga of each response buzzer device A, A2 is configured to generate a ringing tone regardless of whether AC or DC voltage is applied, and in this case, it receives an AC signal of 1'6Hz. to make the speaker Pa sound. Next, when either telephone T1 is picked up, the ringing signal from the station stops and the line voltage remains at a constant DC level. Depending on the other party's business, the necessary power to transfer to the telephone T2 in the next room (in some cases, the call switch Su+ is suppressed).

When the ringing switch SW is closed, the line voltage decreases, and the voltage change detection circuits of both answering buzzer devices A and A2 detect this and switch the switching contacts from aa to bb, changing the voltage of the ringing tone generation circuit Ga. A ring tone is generated by connecting to a source E. Next, the Bunsch button-type call switch.
When you release your hand from the notch 5lll, the switching contact returns and the ringing tone also stops.

[Effects of the Invention] As described above, in the present invention, a voltage change detection circuit and an impedance are connected to the telephone line instead of the response buzzer sound generating circuit that was conventionally used by connecting to an idle line.
By pressing the ring switch, impedance is applied between the lines to change the voltage between the lines, and by detecting this voltage change, the ring tone generation circuit is switched to the voltage source and the speaker sounds, so the minimum required It has the advantage of not requiring any extra lines other than the two telephone lines.
This has the effect of significantly reducing construction costs, especially since there is no need to construct a second line when there is no overhead line.

In this embodiment, a DC power source is used as the voltage source, but an AC power source may be used, or the DC blocking capacitor C may be short-circuited by a switching contact.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing one embodiment of the present invention, and FIG.
The figure is a block circuit diagram of a conventional example. L and L2 are telephone lines, L3L is a vacant line, T and T2 are telephones, A1A2 is an answering buzzer device, Ga is a ringer main circuit, Gb is an answering buzzer generating circuit, Pa is a speaker, and D
is a voltage change detection circuit, R is an impedance, Sw is a call switch, E is a voltage source, q is a DC blocking capacitor, aa
and bb are switching contacts. Agent Patent Attorney Ishi 1) Chief Seven Procedures Amendment (Spontaneous) October 1, 1980 Mr. Commissioner of the Japan Patent Office 2 Name of the invention 2-wire response buzzer device 3 Relationship with the case of the person making the amendment Patent application Humanity Place 1048 Kadoma, Kadoma City, Osaka Prefecture Name (
583) Matsushita Electric Works Co., Ltd. Representative Iku Kobayashi 4, agent postal code 530 Voluntary correction, specification of patent application No. 106929/1983, page 6, lines 13-15 [I may...
0 agent to delete 36 characters of KJ to...
Patent Attorney Ishi 1) Choshichi

Claims (1)

[Claims] (1) A ring tone generation circuit that detects the application of voltage and generates a ring tone is connected to the telephone line and the voltage source via a switching contact, and also detects a change in line voltage and switches the above. A two-wire answering buzzer device comprising a voltage change detection circuit for operating a contact point, and an impedance for suppressing a call switch and changing the line voltage by being applied between two strands of the wire, connected to a telephone line.