SU1589423A1 - Calling-speech device of dispatcher communication switchboard - Google Patents

Abstract

This invention relates to a telephone communication technique. The purpose of the invention is to ensure the symmetry of the wires of the subscriber line during the sending of a ring signal. The device comprises a telephone set 1, a ringing loudspeaker unit 2, a key 3, a subscriber line 4, a dispatch unit 5 comprising a ring signal generator 6, a transistor 7, the first, second and third resistors 8-10. The goal is achieved by including a transistor 7 in the emitter circuit of the transistor 7. Selecting the appropriate resistance value of the resistor 10 ensures that the current through the transistor 7 is less than the saturation current, which causes the transistor 7 to work in active mode. 1 il.

Description

The invention relates to a telephone communication technique and may be used in dispatch communication systems.

The purpose of the invention is to provide the symmetry of the subscriber line wires during the sprinkling of the ringing signal.

: The drawing shows the structure of the electrical circuit of the call-and-call device of the disciplining switchboard.

The call center of the dispatch communication switchboard contains a telephone set 1, a ringing speaker 2, a key 3, a subscriber line 4, a dispatch node 5 containing a ring generator 6, a transistor 7, the first, second and third resistors 8 -ten.

The conversational device of the switchboard of the dispatch communication works as follows. ; At the initial moment, the input 1 of the amplifier of the loudspeaker of the common node 2 is connected to the wires of the subscriber line 4 through an isolating capacitor, and the transistor 7 is closed. When (the subscriber is called from the icKoro dispatcher of node 5 from the ringing generator 6, the input current of the transistor 7 receives a periodic sequence of current and currentless currents. During the current sprinkling in the output circuit of transistor 7, the current flows: current flows during current flow : not present. Thus, the transistor; Torus 7 provides the frequency of the sound generator to the alternating current line, this alternating current through the wires of the subscriber line 4 and through the separation capacitor enters the input of the call amplifier Foot present hands-free unit 2, ensuring that the ringing voltage to the input of the latter. This voltage is supplied. a speaker, whereby the user hears the ringing tone.

In this device, to ensure the symmetry of the wires of the subscriber

line 4 in the emitter circuit of transistor 7 includes a resistor 10. The resistance value of the resistor 10 is selected from the ratio

50

5 Q

Rg R.

Bp

and,

five

where E- is the voltage of the power source;

Claims (1)

and - voltage amplitude of the ringing signal generator b. In this case, the condition is ensured that the current through the transistor 7 is less than the on-current current, which causes the operation of the transistor 7 in the active mode. Invention Formula A call center of the dispatching commutator switch containing a telephone set on the subscriber’s side and a calling volume. The main node is connected via a key to the subscriber line wires to which the control room is connected to the other side, the base of which is connected to the output the ring signal generator, the power source, plus and minus of which are connected to the first and second wires of the subscriber line, respectively, through the first and second resistors, as well as the third resistor, characterized by that, in order to ensure the symmetry of the wires of the subscriber line during the sending of a ringing signal, there is a collector in the control room; the transistor is connected to the first subscriber line, the emitter of the transistor is connected to the minus of the power source via the third resistor, and the resistance values of the first or the third third Pvj resistors are chosen from the ratio  Ej and ,,. where E f, is the voltage of the power source; and - amplitude-voltage generator of the ringing signal.