JPS6027294A - Key telephone device - Google Patents

Abstract

PURPOSE:To open a main wire immediately when the other party terminates a call, by providing a means which detects automatically that the other party terminates the call during holding of the main wire and releasing said holding automatically with this means. CONSTITUTION:If the other party hooks on a handset to terminate the call during holding of the main wire, a DC voltage impressed across main wire terminals L1 and L2 is cut off momently by the action of a telephone exchange connected generally between this device and the other party, and therefore, a light emitting diode D2 is extinguished momently. Consequently, in this case, a photo transistor TR2 is turned off momently, and a high-level signal is outputted to an output terminal A momently. The output terminal A is connected to a plunger or the like which releases the lock of a holding button of the key telephone device though this connection is not shown in a figure; and when the high- level signal is outputted to the output terminal A, the lock of the holding button is released, and a holding switch 2 is turned off. In this state, the main wire is opened automatically and is returned to the original state.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a key telephone device having a hold function.

Conventional Structure and Problems Generally, in a key telephone device having a hold function, the central office line circuit is structured as shown in FIG. In Figure 1,
J is a resistor 11.J connected between the station line terminals L1 and L2. ,
, a capacitor C1, a light emitting diode D1, and a phototransistor TR that operates upon receiving light from the light emitting diode D1.
, 2 is a hold switch that is turned on by suppressing the hold button provided on the button telephone;
3 is connected on the primary side to the hold music input terminals 1-I, 2, into which music and other hold sounds are input, and on the secondary side is connected between the office line terminals L1 and L2 via the hold switch 2. This is a transformer for sending hold music.

%J, Ts 几 is a communication path terminal connected to a button telephone, and C is an output terminal of the incoming call detection circuit l.

In FIG. 1, when an incoming call signal is input to the office line terminal L2, it is detected by the incoming call detection circuit 1 and appears at the output terminal C. Therefore, the incoming call signal appearing at the output terminal C can drive the key telephone to notify that there is an incoming call.

When the telephone is answered using the button telephone and the hold button is operated, the hold switch 2 is turned on and the central line terminals L2 and 2 are connected in a direct current manner, so that a so-called hold state can be established. Then, when the hold state is set, the music and other hold sounds applied to the hold sound input terminals I-1, I(2) are sent to the station line terminals Ll, R via the transformer 3.
If the message is not transmitted to the second party, this allows the other party to be informed that the message is on hold.

In this way, conventional pushbutton telephones are also configured so that they can be put on hold by pressing the hold button, but with this type of telephone, even if the other party is impatient and ends the call while on hold, , therefore no means were provided to detect this.

OBJECTS OF THE INVENTION The object of the present invention is to eliminate the above-mentioned conventional drawbacks, and to provide an excellent key telephone device that has a simple configuration and can immediately open the central office line when the other party ends the call. It is.

DESCRIPTION OF THE INVENTION The present invention provides means for automatically detecting when the other party ends the call while the telephone is on hold, and is configured such that the holding is automatically canceled by this detecting means.

DESCRIPTION OF EMBODIMENTS FIG. 2 is an electrical connection diagram of an embodiment of a central office line circuit used in the button telephone device of the present invention. Indicates something with the same function. 4 is a detection circuit that detects the local current flowing through the hold switch 2 when the hold button is pressed and the hold switch 2 is turned on;
Light emitting diode D2, phototransistor T]1. ．．
It is composed of Nyoto.

Note that C2 is a capacitor for cutting direct current, 1] to D7 are rectifying diodes, and A is an output terminal of the detection circuit 4.

In the above embodiment, when an incoming call signal is input to the office line terminal Lli''2, it is detected by the incoming call detection circuit l consisting of a resistor It, a capacitor 01, a light emitting diode D1, a phototransistor T1, etc., and the output terminal C Therefore, if the button telephone is activated by the incoming call signal that appears at the output terminal C, and you answer with the 〇 button telephone that notifies you of the incoming call, and then press the hold button, this will cause The connection between the hold switch 2 turned on, the central line terminal, and R2 is the hold switch 2 and the resistor 1'L.
2, R3, the light-emitting diode D2, etc., without being closed in the 1α flow, it is possible to put it in a so-called suspended state. When the hold state is on hold, the music and other hold sounds applied to the hold sound input terminals 114.1-12 are transmitted to the central office line terminal 1□, via the transformer 3, the resistor 1t2, the contenza C2, the hold switch 2, etc. No way it will be transmitted to 1 or 2, the other party is $1! You can notify the client that the request is on hold.

When the state is put on hold, a constant DC voltage is applied to the light emitting diode D2 constituting the detection circuit 4 via the hold switch 2 from the central line terminal 1 to the R2 side.
Phototransistor i'IL is in an on state. Therefore, in this state, no output appears at the output terminal A of the detection circuit 4.

When the other party hangs up the handset and ends the call while on hold, the direct current voltage applied across the central office line terminals R2 and R2 is generally cut off momentarily due to the action of the telephone exchange connected to the other party. Therefore, the light emitting diode D2 is also momentarily turned off. Therefore, in this case, the phototransistor rIL2 is also momentarily turned off, and a signal at the noise level is momentarily outputted to the output terminal A. Although output terminal A is not shown, it is connected to a plunger or the like that unlocks the hold button of a key telephone. Therefore, when a high-level signal is output to output terminal A, this causes the above-mentioned The hold button is unlocked and the hold switch 2 is turned off. Therefore, in this state, the central office line is automatically opened,
Return to original state.

Effects of the Invention As is clear from the above-mentioned embodiments, the present invention provides means for automatically detecting when the other party ends a call while the central line is on hold. Therefore, even if the other party ends the call while the central line is on hold, there is no possibility that the central line is still disconnected, making effective use of the central line. It has the advantage of being able to

In addition, in the embodiment, when the other party terminates, the office line terminal L1.1.2
A telephone exchange is used that momentarily cuts off the DC voltage applied to the telephone, which notifies the key telephone on hold that the call has been terminated, but other information may indicate that the other party has terminated the call. It goes without saying that the same configuration can be made by using a telephone exchange that notifies the user of the call.However, in the embodiment, the hold button is locked to maintain the hold state, and the local current detection circuit is The lock of the hold button is released for one night by the output of the local current detection circuit, but an electronic circuit is used as a means to maintain the hold state, and the It goes without saying that it is possible to configure the system to control the circuit and release the pending state.

[Brief explanation of drawings]

FIG. 1 is an electrical wiring diagram of a central office line circuit used in a conventional button telephone device, and FIG. 2 is an electrical wiring diagram of an embodiment of a central office line circuit used in a button telephone device of the present invention. . Ll, L2/office line terminal, T, R...communication line terminal, J13
, H2 hold music input terminal, 1... incoming call detection circuit, 2 hold switch, 3 hold music sending transformer, 4... local current detection circuit, C1A... output terminal.

Claims (1)

[Claims] When you press the hold button on a pushbutton telephone, the central line hold switch will put the central line on hold, and if the other party ends the call while the central line is on hold, this switch will automatically put the central line on hold. A button telephone device comprising: means for detecting the state of the holding switch; and means for restoring the hold switch to its original state by the output of the detecting means.