DE427812C - Circuit arrangement for testing lines at workplaces in telephone systems - Google Patents

Description

GERMAN EMPIRE

ISSUED ON April 19, 1926

REICH PATENT OFFICE

PATENT LETTERING

- M 427812 CLASS 21a ³ GROUP

(S 65734 VIll \ 2ia?)

Patented in the German Empire on April 12, 1924.

The invention relates to the testing of lines in telephone systems, in particular in those in which connections are made in whole or in part via workplaces by a civil servant.

In the commonly used test method for lines accessible from workplaces, when the line to be occupied is occupied via the sleeve of the pawl assigned to it and Generated a cracking noise through the tip of the connecting plug in the officer's telephone. In order to convey a sure signal to the officer, however, it has been suggested that an optical busy signal either when the line concerned is seized or continuously to be activated while this line is busy. But for this purpose everyone must Cord circuit a special test relay or a special test switch for connection be assigned to a test device common to several cord circuits.

The purpose of the invention is to provide a test device that is common to several cord circuits to be brought into connection completely automatically with the cord circuit to be used. This is accomplished according to the invention achieved that a common test device through the one free cord current

*) The patent seeker indicated the following as the inventors:

Alfred Scheimert and Fran \ Simon in Charlottenburg:

circuit selecting switch devices is connected to the cord circuit.

As an exemplary embodiment, a circuit is shown schematically in the figure which shows the application of this test method for the workplace of a control cabinet is.

If the officer at the control cabinet is called by another officer, does ίο a relay 2 (not shown) speak via a service line? at. This includes at its contact T ₁ via the rest contact P ₁ and an interrupter U _{1 is} a circuit for the rotary magnet D of the free status message selector W. The α of the shifting of the free status message selector swept contacts are interconnected and applied to the contact r% of the relay 72nd The selector W is now switched forward step by step by its rotary magnet D until a free cord circuit is found. In this case, the relays P and X respond in a circuit which extends from earth at contact r ₂ via the switching arm a, the windings I and II of the test relay P, the disconnect button T, the switching arm b, the winding of the relay X, extends the contact s of the plug seat switch and the lamp AL to the battery and earth. The test relay P interrupts its contact ^ the circuit of the rotary magnet D, so that the vacancy selector W is stopped. The high-resistance winding I of the relay P is short-circuited via the contact p _{z of} the relay P and an interrupter U _{2 is connected} to the circuit of the call lamp AL . This flicker symbol (lamp AL) tells the clerk of the control cabinet the cord to be used for the connection. The relay X , however, remains constantly energized via the contact r ₂ and the winding PI and applies the common test relay Pr to the plug tip of the plug Si via its normally open contact x _ä. When the plug is lifted, the contact s of the plug seat switch is thrown. To check the condition of the line to be occupied, the officer touches the sleeve of the latch X / with the tip of the plug. If the desired line is occupied, the battery is connected to the jack sleeve via the c-wire of another plug, so that the test relay Pr responds via the contact x _s , the wire a _v the plug tip, jack sleeve and c-wire of another plug. The busy lamp BL is switched on via the contact pr of the relay Pr. If, on the other hand, the desired line is free, the test relay Pr cannot respond and the connection is established in the known manner.

By pressing the disconnect button T , the officer releases the free reporting selector W for further traffic and interrupts the circuit of the relay X. The contact c is assigned to the isolating relay of the place called, which comes into action when the desired officer reports. This interrupts the circuit of the call lamp AL at contact c, while at the same time the cord circuit used is made occupied by applying earth to contact X ₂ and the winding of relay X to contact W for the duration of the connection.

If the cut-off relay is released by disconnecting the connection at the called place and thereby the contact 0 is switched, a circuit for the lamp AL is closed, which extends from earth via the contact X ₂ , the contact c, contact s and the lamp AL extends to battery and earth. It should also be mentioned that the lamp AL now burns continuously, while it lights up intermittently when the line circuit is occupied by the vacancy detection selector. After removing the plug St from the pawl Kl , the contact s of the plug seat switch is turned over again, so that the lamp AL goes out and the cord circuit is released for further use. ■

When the test relay Pr was applied to wire « _{x of} the cord circuit, it was interrupted backwards in order to avoid cracking noises in the receiver of a possibly connected intercom or the intercom of an officer. It should also be mentioned that only a single test relay and a busy lamp are provided for all cord circuits of a workplace.

Claims (2)

Patent Claims: 1. Circuit arrangement for testing lines at workplaces in telephone systems, characterized in that a common testing device (relay Pr) is switched on by the switching devices (free signal selector W) which selects a free cord circuit to the cord circuit. 2. Circuit arrangement according to claim 1, characterized in that an auxiliary switching means (X) is brought into effect via the switching devices (W) which selects a free cord circuit, which switches on the common test device (Py), disconnecting the voice lines of the cord circuit. For this purpose ι sheet of drawings.