JP3033119B2 - Interphone ringer switching circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to an interphone ringing sound switching circuit, and improves an amplifier configuration when a base unit returns a confirmation sound in response to a call from a slave unit. It was done.

(Prior Art) A conventional intercom system is shown in FIG.

In FIG. 2, the intercom system is a master unit 1
And two intercom slave units 2, 3 as slave units. In addition,
The base unit 1 has a circuit for indoor communication, but here, only the terminal P1 connected to the indoor slave unit is shown.

Now, each of the intercom slave units 2, 3 is connected to the intercom input terminals P2, P3 of the master unit 1 via respective lines. Calls by the handset 11 of the intercom slave units 2 and 3 and the base unit 1
From the handset 11 side, bi-directional door phone call amplifier
12, the hybrid transformer circuit 13, the intercom switch 14, and the intercom input terminals P2, P3.
The doorphone changeover switch 14 is connected to the first terminal A when a call is in progress with the doorphone slave 2, and is connected to the second terminal B in a call with the doorphone slave 3.

The signals on the input terminals P2 and P3 are also input to the call detection circuit 15. When a call signal is detected, the call detection circuit 15 generates doorphone discrimination signals 15a and 15b for discriminating from which of the doorphone handsets. Of the intercom identification signals 15a and 15b, the signal 15a controls the intercom switch 14 described above. As a result, when the handset 11 is off-hook, the intercom slave unit having called and the master unit 1 automatically enter a talking state.

The sound source 16, the ringing tone amplifier 17, the capacitor 18, the ringing speaker 19, and the transistors 20, 21 controlled by the doorphone determination signals 15a, 15b from the ringing detection circuit 15,
Based on the calling signal from the intercom slave units 2 and 3, the sound source 16
This is a circuit that loudspeaks the newly generated ringing tone into the room and returns a confirmation tone to the called intercom slave unit. The sound source 16 receives a signal 15b from the call detection circuit 15.
Generates a ringing tone of a tone corresponding to the called intercom slave unit. The signal from the sound source 16 drives the speaker 19 via the ringing tone amplifier 17 and is guided to the emitters of the transistors 20 and 21. Transistors 20, 21
Is set so that the signals 15a and 15b from the call detection circuit 15 are input to the base, and the transistors 20 and 21 are turned off when either one is turned on.

According to the above configuration, in response to a call from the intercom slave units 2 and 3, the speaker is loudspeaked by the oscillation sound from the sound source 16 by the signal 15b to inform which of the intercom slave units has been pressed, and By 15a, the intercom switch 14 is automatically switched to the intercom slave unit that has called. In addition, the intercom units 2 and 3 where the
Is returned through the emitters and collectors of the transistors 20 and 21.

By the way, in the above-mentioned system, if the intercom slave unit 2, 3 is pressed while the master unit 1 such as an indoor call is talking, it is necessary to return a confirmation sound to the intercom slave unit 2, 3.
It is not necessary to make the ringing sound (oscillating sound of the sound source 16) corresponding to the calling from the two or three into the room. A loud ringing tone during a call can disturb the call. Therefore, when a ringing tone sounds, the cutoff switch 24 provided in the ringing tone amplifier 17 is turned on to reduce the amplification factor of the ringing amplifier 17 so that no loud ringing sound is output. Reducing the amplification rate means that the required level of confirmation sound cannot be returned.

In order to return the confirmation sound and not output the ringing sound during the indoor call, return the oscillation sound from the sound source 16 directly to the intercom slave units 2 and 3 or use the route indicated by the dotted line in the figure ( The amplifiers 22 and 23 may be provided between the sound source 16 and the transistors 20 and 21). However, in the case of (1), since the transistors 20 and 21 are used as mere analog switches, no sound is heard on the side of the intercom slave unit, and in the case of (2), a power amplifier is required for each intercom unit.

(Problems to be Solved by the Invention) In a conventional intercom system, when a confirmation sound is returned in response to a call from a door phone slave unit, an oscillating sound of a sound source is louder in a room, and the sound is jarring during a room call. There was an inconvenience of becoming. In addition, it is possible to select to lower the ringing tone level, but there is a fear that the user may forget to restore the ringing tone.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an interphone ringing sound switching circuit in which a confirmation sound is returned to an interphone without raising the ringing sound during an indoor call.

[Constitution of the Invention] (Means for Solving the Problems) The present invention relates to an intercom switch capable of selectively connecting an intercom communication circuit and a plurality of intercom slaves, and a call signal from the interphone slave. And a call detection circuit for detecting a signal from any of the intercom slaves, and in response to the discrimination signal from the call detection circuit, confirming to the indoor loudspeaker and the interphone slave corresponding to each interphone slave. A plurality of sound sources that generate oscillation sounds for
Switching that is controlled based on the discrimination signal from the call detection circuit and operates alternatively in the active region, and is supplied with the output from the sound source to the control pole and amplifies and supplies the output to the called intercom slave unit. Means are provided.

(Operation) According to such a configuration, since the oscillation sound from the sound source is amplified and returned to the intercom that has called, the confirmation sound is always transmitted to the intercom side regardless of whether the sound is loudspeaker indoors. Returned automatically. The switching means for that need only be one transistor for each transistor that can be controlled by a signal from the call detection circuit, and there is no need to provide power amplification means by the number of interphones.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a block diagram showing an embodiment of an interphone ringing sound switching circuit according to the present invention.

In FIG. 1, the same elements as those in FIG. 2 are denoted by strong reference numerals.

The communication line between the intercom master unit (hereinafter referred to as the master unit) 1 and the intercom slave units, for example, the respective door phone slave units 2 and 3, has a handset 11, an intercom amplifier 12, a hybrid transformer 13, The intercom switch 14 is a doorphone changeover switch, and the intercom slave units 2 and 3 are connected to intercom input terminals P2 and P3, respectively. Further, the intercom switch 14 is automatically switched and connected by a discrimination signal 15a from a call detection circuit 15 that detects a call signal from each intercom slave unit 2, 3 from a signal on the input terminals P2, P3. .

Further, a circuit for loudspeaking a ringing tone newly generated from the sound source 16 into the room based on a ringing signal from the intercom units 2 and 3 is performed by a ringing tone amplifier 17, a capacitor 18 and a speaker 19. A switch 24 for ON / OFF or volume down is attached to the ringer amplifier 17,
It is possible to select whether to oscillate the oscillation sound from 16 into the room.

In the present embodiment, the circuit that returns the confirmation sound to the intercom slave unit that has called is provided with the oscillation sound from the sound source 16 and the capacitors 27, 2
This is performed by transistors 25 and 26 which are input to the base via 8 and are derived from the collector. Transistors 25 and 26 are
It is set to operate in the active area, and intercom identification signals 15a and 15b are input to the base via the resistors 31 and 32, respectively. Thus, when one of the transistors 25 and 26 is operating in the active state, the other is cut off. The collectors of the transistors 25 and 26 are connected to the power supply Vcc and to the doorphones 2 and 3 via the doorphone input terminals P2 and P3. Further, the emitters of the transistors 25 and 26 are each grounded.

According to the intercom system having the above-described configuration, for example, when a ringing sound is generated from the intercom slave unit 2,
This signal is input from the terminal P2 to the first input terminal A of the intercom switch 14 and the call detection circuit 15. The call detection circuit 15 generates a level determination signal 15a for operating the transistor 25 in the active region, and this signal 15a is a control signal for switching the intercom switch 14 to the first terminal A side. Further, the call detection circuit 15 supplies the discrimination signal 15b to the sound source 16, and controls the sound source 16 to switch to an oscillating sound indicating the tone of the intercom 2. This oscillating sound is loudspeaked into the room via a ringing amplifier 17, a capacitor 18 and a speaker 19, and is also transmitted through a capacitor 27 to a transistor 25.
Enter the base. The transistor 25 is operating in the active region by the signal 15a, whereby the oscillating sound from the sound source 16 is led out from the base of the transistor 25 to the collector, and is amplified by the door phone slave unit 2 via the terminal P2 (confirmation). Sound loudspeaker). At this time, the transistor 26 does not leak the signal from the capacitor 28 since the input level to the base by the determination signal 15b is low.

The operation of the transistor 25 in the above is the same even when a call is made from the intercom slave unit 2 during an indoor call, and it is possible to surely perform room loudspeaking and return of a confirmation sound.

Here, if you do not want room loudspeaker,
What is necessary is just to set the switch 24 of 17 to ON. That is, the transistors 25 and 26 are connected to the intercom identification signal 1 of the call detection circuit 15.
Depending on 5a, 15b, one of the transistors 25, 26 becomes O
N, and when the other is turned off, the oscillation sound from the sound source 16 is
2, has a switch function to supply to one of the intercom slave units 2 and 3 via P3, and when the transistors 25 and 26 are turned on, they operate in the active region, so the oscillation sound from the sound source 16 is amplified. Then, it has an amplifying function of supplying to the intercom slave units 2 and 3 via the terminals P2 and P3. As a result, the confirmation sound of the predetermined oscillation volume can be amplified in the intercom slave units 2 and 3 without being affected by the increase / decrease of the amplification gain due to ON / OFF of the switch 24 of the call amplifier 17. Further, when the operation of the switch 24 is forgotten, for example, the switch 24 may be automatically controlled based on an output from a means for detecting the end of the indoor call.

According to such a configuration, it is possible to perform indoor loudspeaker switching and return a confirmation sound without changing or increasing the conventional configuration or the number of parts.

[Effects of the Invention] As described above, according to the present invention, when there is a call from an intercom slave unit without changing or increasing the number of components and parts of a conventional intercom, the intercom master unit can perform an indoor call. Do not call during the middle
In addition, there is an effect that a confirmation sound of a required volume is reliably returned to the calling intercom slave without interrupting the main unit indoor call.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an interphone ringing sound switching circuit according to the present invention, and FIG. 2 is a block diagram showing a conventional interphone ringing sound switching circuit. 1 ... Master unit, 2,3 ... Intercom slave unit, 11 ... Handset, 12 ... Intercom amplifier, 13 ... Hybrid transformer, 14 ... Interphone changeover switch, 15 ... Call detection circuit, 16 ... Sound source, 17 …… Ring tone amplifier, 19 ……
Speakers, 25, 26 ... transistors, 27, 28 ... capacitors, 29-32 ... resistors.

Claims (1)

(57) [Claims] An interphone communication circuit; an interphone change-over switch for selectively connecting the interphone communication circuit and a plurality of intercom slaves; and detecting any one of the interphones by detecting a call signal from the intercom slave. A call detection circuit for judging whether or not the signal is from the handset; and in response to the judgment signal from the call detection circuit, generating an oscillating sound for the room loudspeaker corresponding to each intercom handset and for confirmation to the interphone handset A plurality of sound sources; and a plurality of loudspeaker means for loudspeaking the output from the sound source into a room; a plurality of loudspeakers provided corresponding to each of the intercom slave units; A switching means that operates at the same time as the output from the sound source is supplied to the control pole and is amplified and supplied to the intercom slave unit that has called. Intercom ringing tone switching circuit, characterized in that it comprises a.