SU57628A1 - Device for communication of remote subscribers with an automatic telephone exchange (PBX) or manual telephone exchange (RTS) of the Central Bank system - Google Patents

Description

On urban telephone exchanges, it is common for subscribers to have a loop resistance that exceeds the allowable subscriber line resistance.

In the practice of operating telephone exchanges of the Central Bank system to turn on remote subscribers, various special schemes are used, containing from one to several relays and requiring the installation of MB systems from such subscribers,

Application of the CB system under these conditions is impossible for two reasons: firstly, due to insufficient operating current in the line for normal operation of station relays and, secondly, due to insufficient power of the microphone of the Central Bank’s device due to a large voltage drop, which should cause an unacceptable drop in line level.

The use of MB systems on remote subscribers has a number of disadvantages, such as: the need to use local power sources for subscribers;

relative complexity of user use by the subscriber; the inability to turn on MB devices in the PBX system, etc.

According to the present invention, for a communication device of remote subscribers with an automatic telephone station (PBX) or a manual telephone station (RTS) of the CB system, in order to increase the microphone power supply current and ensure the stability of station relay operation, the subscriber’s microphone is powered through phantom ground the circuit formed by the two wires of the subscriber line. In this way, the subscriber’s power supply device achieves a reduction in line resistance for direct current, and consequently, an increase in the microphone power supply current. At the same time, the attenuation of conversational frequency currents remains unchanged, since their transmission is carried out along a two-wire circuit. For a remote subscriber, the device of a special scheme is turned on, to which the name of the device is assigned (cerebral securities (differential securities)).

At the station, the DCB apparatus is switched on according to a scheme containing a differential transformer, a relay and a capacitor using a normal subscriber set.

The drawing shows the inclusion, according to the invention, the apparatus of the cerebral systemus in the line of the remote subscriber.

The action of the scheme is reduced to the next.

When the subscriber picks up the microtelephone tube, a circuit is formed: minus, XRT relay at the station, middle point and both transformer windings, both wires of the line, both windings and middle point of the transformer in the subscriber unit, pulse dialer contact, microphone and microphone transformer winding and parallel resistance to them R, additional switch contact, ground

Resistance R is connected in parallel with the microphone and the microphone winding of the transformer in order to eliminate the possibility of a false tampering phenomenon.

A parallel capacitor (20-100 1J.F), for example electrolytic, is connected in parallel with the resistance / to form a microphone circuit with low resistance for the variable component of the microphone current.

When dialing, the subscriber, as usual, uses the dialer, the impulse contact of which is included in the phantom microphone power supply circuit. From the action of pulses P}, the RLT relay, which transmits pulses to a linear PBX set, is used.

The inclusion of a call in the cerebral march apparatus is made without a barrier capacitor, since the need to use the latter, in view of the passage of direct current through two wires through the ground, is no longer necessary.

The subject matter of the invention.

Claims (4)

1. A device for communication of remote subscribers with an automatic telephone station (PBX) or a manual telephone station (RTS) of the CB system, characterized in that, in order to increase the microphone supply current and ensure stable operation of station relays, the subscriber’s microphone is powered through ground through a phantom circuit formed by two wires of the subscriber's line, closed on differential transformers, the midpoint of the linear winding of one of which, installed at the station, is connected through the winding of the transmitting line Foot switch RLT to minus earthed battery, and the midpoint of the linear winding another, present in the subscriber telephone set, is connected via a microphone and microphone winding of the transformer to ground via a further switch contact, upon release of zamykayuschiys microtelephone. 2. In the device according to claim 1, use in the subscriber's telephone set of active resistance R connected in parallel with the microphone and the microphone winding of the transformer in order to eliminate the possibility of the occurrence of a false taps. 3. In the device according to claims. 1 and 2, a capacitor of a large capacity, in particular an electrolytic capacitor connected in parallel with the resistance /, is used in the subscriber's telephone set to form a local microphone circuit with low resistance for a variable component of the microphone current. 4. The form of the device according to paragraphs. 1, 2 and 3, for the purpose of using it for a PBX subscriber, characterized in that the pulse dialer contact is connected between the middle point of the differential transformer and the microphone, and the dialer shunt contact is connected between its pulse contact and the grounding switch of the switch. copyright certificate Yu. R. Gints No. 57628 Not a single name / act aa