SU1238262A1 - Device for automatic switching-off call - Google Patents

Abstract

This invention relates to telephony and can be used in test devices. The purpose of the invention is to simplify the device by eliminating the power source. The device contains two two-half-period bridge rectifiers. . . if 9 (pres) I and 13, consisting of diodes 2-5 and 14-17, optocoupler 6, capacitor 7, the chip of the 8-M resistor and two np-r-transistors (T) 12 and 18. In the original A constant power supply voltage from a subscriber telephone line (ATL) is supplied to DNV 13, providing constant power to T 12 and 18, which do not load ATL. When a call is received from the ATL, the alternating current through the co-sensor 7 goes to DNV 1. From the DMV 1 output, rectified current, limited by the resistor 8, enters the optocoupler 6, the T 12 openings, and 18, which were located in the state of maximum transient resistance. At T 12 and 18, the output impedance is switched to the minimum state, which ensures the closure of the ATL loop, which is the user response. The goal is achieved by introducing a pressure of 13 and T 18. I Il. em.

Description

The invention relates to telephony and can be used in test equipment, built-in equipment for monitoring and diagnosing PBXs, as well as a set-top box for a telephone set that provides for the automatic rejection of incoming calls upon the demand of the called subscriber.

The aim of the invention is to simplify the device by eliminating the power source.

The drawing shows the principle. Phial edek: griceka automatic call disconnect.

The device contains a two-half-bridge bridge rectifier 1, consisting of the first 2, second 3, third 4 and fourth 5 diodes, optocoupler 6, capacitor 7, first 8, second 9, third 10 and fourth 11 resistors, pnr transistor 12, an additional full-wave bridge rectifier 13, consisting of a fifth 14, sixth 15, seventh 16 and eighth 17 diodes, and an additional pnp transistor 18.

The device works as follows.

In the initial state, the constant supply voltage from the subscriber telephone line is postponed to the first diagonal of the additional two-sided bridge bridge rectifier 13, providing the corresponding constant power to the pn-p-transistor 18, regardless of Polarities on the first and second wires of the subscriber telephone line. In addition, the pn-transistor 12 and the additional pn-transistor 18 do not load the subscriber's telephone line.

When a call comes in from the subscriber's telephone line, the alternating current through the capacitor 7 is fed to the full-wave 1st bridge switch 1, the output of which rectifies the current limited by the resistor 8 to flow through the light-emitting diode of the optocoupler 6. As a result, the photodiode of the optocoupler 6 opens. a pnp transistor 12 and an additional pnpn transistor 18, which were previously in the state of maximum output impedance, at the same time they go to the minimum

output impedance to close the loop of the subscriber telephone line, imitating the subscriber's response.

After the transmission of a signal simulating the response of the subscriber, the call signal from the subscriber telephone line is terminated and the automatic call disconnect device returns

in the initial state, providing

removing a loop from a subscriber's telephone line, i.e. imitation hang up the called subscriber. Thus, due to feedback arising

when the loop is closed on the subscriber's telephone line under the influence of a ringing signal and the subsequent disconnect of this signal from the subscriber's telephone line after

sending a response signal to the subscriber, automatically controls the state of the loop.

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Claims (1)

Invention Formula An automatic call disconnect device containing a full-wave bridge rectifier, consisting of first, second, third, and fourth diodes, an optocoupler, a capacitor, the first, second, third, and quarter resistors of an ip-ppn transistor, and the combined cathodes of the first and .second diodes connected to anode the light-emitting diode of the optocoupler, whose cathode is connected through the first resistor e by the combined anodes of the third and fourth diodes, the cathode of the photodiode of the optocoupler is connected via a second resistor to a npp transistor collector, the base of which is connected to the anode of the photodiode of the optocoupler and, through the third and fourth resistors - with emitter The pnp transistor, the combined anode of the first and the cathode of the third diode are connected to the first wire of the subscriber's telephone line, and the combined anode of the second and cathode of the fourth diode are connected via a capacitor to the second wire of the subscriber's telephone line, tl and h - with the fact that, with the simplification circuit of the device by excluding is-. power supply, an additional full-wave bridge is added, consisting of the fifth, sixth, seventh, and eighth diodes, as well as 3, 1238262. four additional npn transistor, surrounding an additional npn transistor, the base of the additional npn trans and the point of connection of the third and of the resistor is connected to the emitter of the pnp fourth resistor, while the transistor, the combined cathodes, the common anode of the fifth and the cathode of the seventh and sixth diodes are connected to the diodes connected to the first distributor of the additional subscriber telephone line to the transistor and the cathode of the photodiode opt-the second wire of which are connected pona, combined anodes of the seventh and combined anode of the sixth and cathode Eighth diodes are connected to emitte-eighth diodes.