SU105231A1 - Method of making a tone selective call - Google Patents

Description

This invention relates to a method for controlling selective devices during control transfer. pulses by currents of frequent currents on the telephones of the telephone.

The methods used in existing systems for making a selective call over long-distance telephone channels by tonalpical frequencies are based on the transmission of a numeric code to selective

device, NOSTOYANPO CONNECTION) to these communication channels. In this case, it is very difficult to protect selective devices from false triggering under the influence of conversational currents.

The proposed method for making a selective call by tonal frequency currents involves sending a one-digit numeric code corresponding to the graph shown in FIG. one.

As can be seen from the graph, before the beginning of the transmission of the pulses of a set, a preliminary impulse is sent to the directing tonal frequency with a duration exceeding 1200 m / s.

Php1 2 shows a skeleton control circuit for switching on a set of devices, in particular the following designations: PI receiving relay; L | -C - Ri-electron pe.ic; Do to Do-repeat.pie pe; i; u and i contacts; - modulator; D-demodulator; DS-differential system; PTP-gfeempik tonal impulses; 1 ,, - resistance. B is balance.

The receiving relay And, operating continuously for the time of switching on the selective device, acts on the electronic relay (lamp D1) and triggers the repeater relay U activated in the anode circuit of the lamp Dk

Short pulses perceived by the receiving relay during a conversation cannot trigger the electronic relay, since their duration does not reach 1200 m / s, and even the release of the receiving relay causes charge generator C in the circuit of the electronic relay and restoration of the nervous system.

Repeating relay U, bringing the measles, closes the circuit of the winding of the relay U, which connects the selective

device. The operation of the relay Y becomes independent of the relay Y by holding the measles in the closed-contact circuit of the relay I.

As can be seen from the graph (Fig. 1), the set pulses are transmitted in the form of momentary interruptions of the control frequency current. These pulses are perceived by the selective device in time with the release of the receiving relay I. The relay .Vl does not release the core, since the opening time of the contact of the pulse relay during all dialing pulses, except the last, is slowed down by OToyciia.

The last NMR of the set is expressed in the prolonged cessation of the control frequency transfer. It is also perceived by the selective device and at that time causes the release of the cortex of the main control relay. At this moment, the perceived code is fixed in the selective device. The selective device is turned off until a new pre-impulse of the control frequency is obtained that is longer than the response time of the electronic relay.

Thus, the proposed method of making a tone-selective call is based on the use of a single-digit number code combining:

a) long-term arrival of the control frequency, allowing the selective device to be connected;

b) short-term interruptions in the arrival of the control frequency, perceived by the selective device as dial pulses;

c) long-term termination of the arrival of the control, its frequency, perceived by the selective device as the last pulse of the dial and as a signal for the disconnection of the selective device itself.

Subject and d on and e and

Claims (3)

1. A method for making a tonal selective call, sent by a one-to-one numeric code by discontinuing the control frequency current parcels, of a tl and h with the fact that before the start of the dialing pulses, a pre-specified control pulse is sent. frequencies. 2. Method n. 1, is different from HJ. and with the fact that, in order to exclude false positives of the counting (selective) device as a result of the influence of conversational currents on it, it is connected before the end of this preliminary current control of the frequency. 3. The method according to claim 1, characterized in that when the current is stopped for a certain time, which exceeds the transmission time of one dialing pulse, the counting device is disconnected from the receive circuit.