JPS5917920B2 - Alternate conversation intercom - Google Patents

Description

[Detailed description of the invention] The present invention provides an alternate call type interface with improved operability.

-Regarding Hon. Traditionally, intercoms with alternating calls have a switch for switching between transmitting and receiving, and a switch for supplying power to an amplifier during a call, and when receiving a call, the power supply switch is turned off to turn off the amplifier, and a call switch is also provided. When pressed, the oscillator and amplifier are energized and ready to receive a ringing tone.

Therefore, it is necessary to operate two sets of switches when making and ending a call, and there is also the problem that during the operation, the battery may be exhausted due to forgetting to return the power supply switch. . On the other hand, in order to solve these difficulties,
There is a known intercom with a timer circuit that keeps the amplifier active for a certain period of time (Utility Model No. 53-130).
Publication No. 910).

However, in this circuit system, the timer circuit is directly driven by the switch, and the timer setting time T after the switch returns. is set and the call is forced to end, and the call reception time T
There is no problem when rl is shorter than To (Figure 2 a), but
The listening time Tr2 is T. If the time is longer, it becomes impossible to receive calls after the amplifier operating time T1 (FIG. 2b). To prevent this, if you turn on the switch again, the timer will be set again and the amplifier will operate, but the time from when you can no longer receive calls until you press the switch is 2' and the time when the switch is turned on. During the total time Tr3', there will be no reception of calls (FIG. 2c). As described above, this method has the drawbacks of interrupting the reception of the call and making it cumbersome to operate the switch again. The present invention was made as a result of intensive research in order to solve the above-mentioned difficulties, and includes one transmitting/receiving switch and a time limit circuit driven by an output signal from an amplifier. A device that is applied as a driving source to a time-limited circuit that continues for a certain period of time, and automatically cuts off the power supply to the amplifier unless there is another output signal within that certain period of time, achieving an "automatic recovery" function. It is.

Hereinafter, the present invention will be explained in detail by way of examples.

In FIG. 1, reference numeral 1 denotes a handset, which has a handset 3 which is a speaker that also serves as a microphone, and a call switch 5.

2 is the base unit, and the handset 4 is a speaker that also serves as a microphone.
An oscillator 12 and an amplifier 14 driven by the call switch 5, and a time limit circuit 10 that maintains the amplifier for a certain period of time.
and switches 6, 7 for alternately switching the transmitting/receiving state of the handsets 3, 4.

The parent and child devices are connected by two lines 11 and 12. 8 is a transmitter power set switch, 9 is a call set switch, 1
0 is a time limit circuit for both calling and talking, 11 is a control circuit for controlling the oscillator and maintaining power supply to the amplifier, 12 is an oscillation circuit for calling, and 13 is a time limit circuit that converts a part of the output signal from the amplifier. , 14 is an amplifier that performs calling by the rear-stage amplification section, and communication is performed by the front-stage and rear-stage amplification sections, respectively. 15 is a power supply terminal.

Capacitors Cl, C2, and C3 are for DC blocking. Switches 6 to 9 are of the type that are opened and closed in conjunction with each other, and when they are turned on, they are in the position shown by the dotted line in the figure, and when they are returned, they are in the position shown in the solid line, indicating a standby state. Note that 16 indicates a diode.

Now, when you turn on the call switch 5 on the handset 1,
Power supply terminal 15 - Time limit circuit 10 - Call set switch 9 -
By forming a DC closed circuit of line 11, calling switch 5, line 12, and ground, time limit circuit 10 is set and the latter stages of oscillator 12 and amplifier 14 are brought into operation via lines 13 and 14.

The ringing signal from the oscillator 12 is amplified via a line 16 by a subsequent stage of the amplifier 14, and then transmitted through a switch 7 and emitted from the handset 4 as a ringing tone. When the call switch 5 is reset, the time limit circuit 10 is driven to 1 to maintain the operating state of the oscillator 12 and the amplifier 14 for a certain period of time. In this way, keeping the oscillator and the downstream stage of the amplifier in an operating state for a certain period of time even after the call switch is reset means that, for example, when the ring tone is set to a chime sound, when the call switch is reset, the second stage is activated. It enables sound to be emitted. In addition, in this case, since the control circuit 11 is not operating, the power supply circuit before the amplifier 14 is not supplied via the line 15, so that the power supply circuit from the handset 3 of the handset 1 to the handset 4 of the base unit 2 is connected. cannot transmit audio. Note that the diode 16 is connected to the time limit circuit 10 at the time of calling.
The control circuit 11 operates via the line 17 and serves to prevent the oscillation circuit 12 from being deenergized.

Next, on the base unit 2 side, when the aforementioned ring tone is recognized and the selector switch 6-7 and set switch 8-9 are switched to the positions shown by the dotted lines in the figure, the diode 16 is connected via the power terminal 15 and the set switch 8. - The circuit on line 14 supplies power to the downstream stage of the amplifier 14, and the line 17 operates the control circuit 11 to de-energize the oscillator 12 through line 18, while supplying power to the stage before the amplifier 14 through line 15. Do the following.

For calls (transmission from the base unit to the handset), the handset/receiver 4 switch 6 - capacitor C2 - amplifier 14 capacitor C3 switch J line 1, capacitor C1 - handset 3
- line 12 - by means of a closed circuit of earth.

A part of the audio output signal from the amplifier 14 is supplied to the conversion circuit 13, which converts it from analog to digital, applies it to the time limit circuit 10, and stores it. The control circuit 11 is held at the same time as it is set with a delay of time Δt (FIG. 2 d) until the signal is emitted.

When the audio from the base unit stops after time Tt, the time limit circuit 10
The time limit circuit 10 is driven for a certain period of time using the signal accumulated in the signal as its driving source. Next, when the changeover switch 6-7 and the set switch 8-9 are reset on the base unit 2 side (turn-on time t1), since the time limit circuit 10 is being driven as described above, the line 14 is connected to the downstream stage of the amplifier 14. In addition to supplying power, the oscillator 12 is connected to the line 18 by the control circuit 11 held when transmitting a call from the base unit 2 to the slave unit.
line 15 before amplifier 14.
Power is supplied via.

For calls (receiving calls from the handset to the base unit), use the handset 3 capacitor C, - line 11 switch 6 - capacitor C2 - amplifier 14 - capacitor C3 switch J.
– by means of a closed circuit of earth; A part of the audio output signal from the amplifier 14 is supplied to the conversion circuit 13, which converts it from analog to digital, applies it to the time limit circuit 10, stores it, and maintains the set state while the audio from the handset continues. are doing.

As shown in FIG. 2d, when the sound from the handset stops after time Tr, the time limit circuit 10 is driven for a certain period of time (TO) using the signal accumulated in the time limit circuit 10 as its driving source, and then the time limit is released. In response to this, the power supply to the subsequent stage of the amplifier 14 is stopped for a time T.
It stops after 1, and the control circuit 11 is considered a failure. When the control circuit ceases to operate, the oscillator 12 is no longer deenergized, and the power supply to the front stage of the amplifier 14 is also stopped, resulting in automatic recovery to the standby state. As is clear from the above embodiments, according to the present invention, a part of the output signal from the amplifier is used as a drive source for driving the time limit circuit, so that the time limit circuit is operated even when the audio output signal disappears. Since it is activated from It can provide a talking intercom.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the intercom of the intercom system according to the present invention, and FIGS. 2A to 2C and 2D are explanatory diagrams of the operation of the intercom of the prior art and the present invention, respectively. 1... Child unit, 2... Base unit, 3, 4...
...Transmitter, 5...Call switch, 6,7
......Changing switch, 10...Time limit circuit, 11...Control circuit, 12...Oscillator, 14...Amplifier.

Claims (1)

[Scope of Claims] 1. A handset and a handset having a handset and a calling switch, an oscillator and an amplifier driven by the calling switch, a time-limiting circuit that sustains this amplifier for a certain period of time, and An alternating call type intercom equipped with a base unit having a switch for alternately changing the transmitting/receiving state of the handset, characterized in that a part of the output signal from the amplifier is applied to the time limit circuit as its driving source. An intercom with alternate communication. 2. The alternating call type intercom according to claim 1, further comprising a control circuit that de-energizes the oscillator during a call.