DE414839C - Circuit arrangement for private branch exchanges connected to a telephone exchange with dialer operation - Google Patents

Description

GERMAN EMPIRE

ISSUED AW S. JUNE 1925

REICH PATENT OFFICE

PATENT LETTERING

- JVe 414839 - CLASS 21 a GROUP 65

(T26860 VHIJ2ia *)

Telephone set factory E. Zwietusch & Co. G. m. B. H. in Charlottenburg.

Circuit arrangement for private branch exchanges connected to a telephone exchange with dialer operation.

Patented in the German Empire on August 20, 1922.

The invention relates to a circuit arrangement for private branch exchanges connected to a telephone exchange with dialer operation, in which therefore devices for number current impulse delivery over the trunk lines are provided for recruiting the voters of the office and the calling device of the According to postal regulations connected to the line during the call remain.

The invention has the purpose for private branch exchanges of this type in compliance with the aforementioned postal regulation an impairment of the call device by the Office sent number bursts, z. B. one to errors or malfunctions in the management the system giving rise to striking or actuation of the alarm clock or a faulty dropping of the call flap impede.

This purpose is achieved according to the invention in that the calling device of each exchange line or this is assigned a relay whose circuit is short-circuited in the operational idle state as well as in the through-talk position of the line, which short-circuit is canceled during the duration of the actuation of a number switch on this . This cancellation ίο the short circuit can be done in a simple manner by a normally closed contact, which opens when pulling the number switch and; is only closed again after the end of the number current impulse caused by the elevator. In order to save electricity, it is advisable not to switch on the said circuit of the relay until ' a speech switch on the exchange line is in the; Talk-through position, which is also the position in which the number bursts are sent to the office, is turned over. The speech switch itself can; with one when you put it in the intercom! position closed contact. {The drawing shows an embodiment of the invention.

The figure shows a circuit arrangement for a private branch exchange with two exchange lines and two workstations. Each of these two places is assigned a speech or exchange switch 5 for each of the two exchange lines and a number switch N with a finger disk for both lines. An AC alarm clock W is provided in the usual manner on each line in front of the office switches. Furthermore, each exchange line is also assigned a relay R which has a normally closed contact 7 in the circuit of the alarm clock of the line, at which the relay interrupts the alarm circuit when it is responded.

The circuit of the relay R runs via the normally closed contacts 11 provided on the number switches and via working contacts on each of the four existing office switches S. The relay R of the relevant exchange line is connected to the battery and also short-circuited at the same time via these working contacts.

The arrangement works as follows:

To establish a connection, e.g. B. from the left seat over the upper line to the office, the switch S is moved from the drawn rest position to its query position, the number switch N of the place is turned on to the upper exchange line and the following circuit is closed at switch 5: from battery B Via line 1, contact springs 2 and 3 of switch S, line 4, winding of relay R, line 5, busy indicator Z ¹ , Z ² and line 6 to battery B. Relay R responds in this circuit. At its contact 7, this interrupts the circuit of the alarm clock W connected to the line, so that it cannot be impaired in any way by the current surges subsequently sent to the office via the line. From the side of the relay R connected to the line 5, a connection leads via the lines 8, 9 and 10, the normally closed contact 11 of the number switch N, the lines 12 and 13 to the contact spring 14 of the office switch S and from the contact spring 14 via the contact spring 2 the same switch and the line 4 to the other side of the relay R. This connection short-circuits the relay, so that the relay R is not energized when the intercom of the officer in the left seat is connected via the switch S and the upper trunk line to the office and so that the alarm clock W is not switched off from the exchange line at contact 7. But as soon as the number switch is pulled up or expires, so his finger washer is out of rest position, the contact 11 is open and thus the short-circuit connection of the relay R is interrupted, the short circuit for the relay R is canceled and this is thus energized, so that now the contact 7 the alarm clock W is kept switched off by the exchange line and thus any impairment of the alarm clock by the number current surges sent to the office is prevented.

Claims (2)

Patent Claims: 1. Circuit arrangement for private branch exchanges connected to a telephone exchange with dialer operation, characterized in that a relay (R) assigned to the exchange line, which is short-circuited in the working position of the main switch (5) by this, the circuit of the calling device (W) during the pulling up and The running of the dial interrupts in a manner known per se. 2. Circuit arrangement according to claim i, characterized in that the relay (R) is only placed on the battery and short-circuited at the same time when the main switch (S) is moved into the working position for the purpose of establishing the exchange connection. 1 sheet of drawings.