SU29512A1 - Device to selectively call two subscribers - Google Patents

Description

Devices are already known for selectively calling two subscribers included in a common two-wire line, in which one wire and ground are not used to power the microphones and make a call to each of the subscribers, and a two-wire circuit is used to transmit a talk-in current.

The present invention consists in a particular form of implementation of such a device.

Each of the A VL B subscribers in the proposed device, schematically shown in the drawing, has a separate number with the normal station equipment related to it, consisting of a VA or VB ringing relay, a PA or RB dividing relay, a survey socket with a calling lamp and a number of nests yltipl (multiple sex). Thus, customer service telephony occurs in a normal way without any additional operations. Subscribers have devices of normal type. A full interlocking condition is that when one of the subscribers picks up the phone, the other is turned off, as well as when the plug is inserted into one jack of one subscriber, the other is noted as busy, and is deprived of

can call station As mentioned above, the DC microphones and the call are powered by one wire and ground, one wire being used for one subscriber, the other for the other, and. the transfer of the talk current to the sound frequency occurs over two wires, and the second wire is connected only for the duration of the line being occupied by the subscriber.

When, for example, the A subscriber picks up the handset, he receives power from the station through his calling relay VA (and when the plug is inserted through the burglary relay): one wire, a rest contact b, an apparatus, a relay DL and ground. Relay DL comes into action, turns off the subscriber / and establishes a two-wire circuit for subscriber A, connect the second wire through the capacitor C3. When inserting a plug into the socket of subscriber A when answering or calling, its separation relay PA with its contact pai turns off the subscriber's VA call relay, and poz turns off the other subscriber's call relay and establishes a two-wire circuit for the talk current.

However, with such a circuit for switching on the devices, the said colloquial circuit

can be broken by inserting the plug into the socket of the second subscriber B, i.e. sending a minus to its RB separation relay connected to the source plus. In this case, the separation relay of the second subscriber B will come into effect and contact p6z will open the conversational circuit of subscriber A.,

To eliminate this drawback, according to the invention, the separation relay of each subscriber is provided with a contact or p6z, which, when the relay is triggered, switch the isolation relay of the other subscriber from battery to minus (directly or through resistance) or give a different signal indicating that the subscriber is busy.

The subject matter of the invention.

A device for selectively calling two subscribers on a common two-wire line, using microphones and a package for powering. to each of the subscribers of one wire and the earth, and for the transfer of a talkative current, a two-wire circuit formed for the time of the line's occupancy, which is to ensure that the free subscriber’s equipment, in case of a line being occupied by another subscriber, each of PA and PB dividing relays are provided with a paz, rb contact, intended to switch another subscriber's | divider relay from plus to minus, or give a different signal indicating that the subscriber’s device is busy.

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