DE208837C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

# ■ PATENT LETTERING

Vr 208837 CLASS 2 \ a. GROUP

WALTER BLUT in BERLIN.

to be used.

Patented in the German Empire on April 13, 1907.

There are already circuits for auxiliary switching cabinets with central battery operation became known at which if the extensions deal with the office, in addition to the office also the person operating the switch automatically receives a final signal when the relevant extension uses its speech set put back in rest position.

In these circuits, however, is mostly

ίο from the electromagnetic effect of the Office supplied feed current for the excitation of relays made use of the necessarily lie in the supply circuits and through means that can be passed for speech currents, such as capacitors, need to be bridged. Experience has shown that such facilities besides disturbances of the line equilibrium there are various other inconveniences in the wake.

According to the present invention, everything that interferes with the communication with the office should now could act, can be avoided by the fact that the trunk line or the central battery current of the office is only reserved for official traffic, the final signal as well as the call signaling for switching operation, however, with the help of special individual signal lines with a common return line as follows The following is effected: The connection of those extensions which are also connected to the switching office are to run, takes place with the extension switch in such a way over three lines, that one of them using a special signal contact, a local battery and earth for call and termination purposes only for the extension switches serves, while the other two lines for trunk connections are used exclusively for trunk traffic, on the other hand, when connecting microphone units to one another, also for final signal purposes serve, in the latter case the connection is made by plug cords, in which one or more final signal relays are switched on in a known manner.

As can be seen from the drawing, this is achieved in the following way:

Extension units N ₁ to N _{3 can be} connected to trunk lines A ₁ to A ₃ using a lever switch A ₁ to A _3. The connection of the same, e.g. B. from N ₁ , is effected via three lines a, l ·, c , the two of which, α and b, are only used for communication with the office in the case of exchange connections, while the third line c is used exclusively for signaling purposes, with special Changeover contacts 7, 8 'of the lever changeover switches A ₁ to A _9, the call and closing signals I ₁ to I ₃ , S ₁ to S ₃ can be switched over.

If the remote receiver 9 of the telephone station N _{1 is} removed from the switch hook, a signal contact 10 is automatically closed in addition to the microphone contacts. As a result, current flows from the central battery B of the switch cabinet via earth, contact 10, line c, contact 11 of the latch A ₁ , relay Y ₁ and back to the battery. The relay r _x pulls its armature and closes the contact 5, so that now current of the battery B via a line 4, contacts 7 of the lever switch A ₁ to A ₃ , a line 15, call lamp I ₁ and via contact 5 back to the battery B flows. If the operator of the switch cabinet notices that,

Claims (3)

Call sign I1, it switches your remote receiver in a known manner into the line of the calling subscriber and brings, if z. B. Connection with the exchange line A1 is required, the lever switch It1 in speech position (see figure). As a result, on the one hand, the. The telephone of the calling extension N1 is connected to the exchange line A1 via the switches A2, A3 directly via contacts 17,18 and is switched off from the jack lines 21, 22 by separating the contacts 19,20, so that the telephone station N1 has just like a normal subscriber line is in contact with the office. By turning the lever switch A1, however, at the same time, as a result of the separation of the contact 7, the call signal I1 is switched off and instead the preparatory contact 8 for the final signal S1 is closed. If, after the end of the conversation, the remote receiver 9 is attached again to intercom station N1, then, since the signal contact 10 is interrupted and the armature of the relay rx falls back into the rest position, its normally closed contact 6, terminator S1, contact 8 of H1, contacts 7 from A2, A3 and line 4 current of battery B, and the person operating the changeover switch switches off both the call station 'N1 from the exchange line A1 and the terminator S1 from battery B by moving the lever switch Jt1 back. The same processes take place in the same way with the other exchange connections. If a call station N wants to be connected to another, the call sign is given exactly as described above, but the connection is then made by inserting connecting plugs ft, q into the jacks k2, A3 z. B., whereby the call relays rx to r3 and thus the call signals I1 to I3 are automatically switched off by separating the latch interruption contacts 11 to 13 and the final signaling afterwards in a known manner by special final signal relays Ra, Rb and lamps m connected between the plug cords, η takes place, whose supply circuit is kept open by switches ζ of any kind in the rest position of the plug. If a connection is to be made between an extension authorized for the exchange connection with another unauthorized intercom (private unit), the connection is also effected by a simple plug connection, whereby of course the handle of the private unit only needs to have a simple break contact to switch off the call relay. An unauthorized connection of not authorized stations with the office can of course never take place, because the jack lines, z. B. 21, 22, through the lever switch, e.g. B. A1, always be separated. Sponsorship τ claims: 1. Circuit for telephone extension switch with central battery operation, in which three lines are used to connect the switch to the extensions, characterized in that the connection of those extensions (N ₁ ) that should also communicate with the exchange with the extension switch in the manner about three lines (a to c) that one of the same (c) using a special signal contact (10), a local battery (B) and earth or common return line is used only for call and closing signal purposes for the extension switch, while the other two. Lines (a and b) for exchange connections are used exclusively for official traffic, but when connecting intercom stations to each other they are also used for terminating signal purposes, whereby in the latter case the connection is made using plug cords (ft, q) into which one or more terminating signal relays (Ra, Rb) in are switched on in a known manner. 2. A circuit according to claim 1, characterized in that the third contact lever (3) of the three-part lever _{changeover switches connected one behind the other in groups ^ A 1} to hg) for switching the return line (4) of the call lamps (I ₁ to I ₃ ) to the tail lamps ^ s ₁ up to S ₃ ) is used for the purpose of connecting an extension (N ₁ ) to the office by turning the relevant lever switch (e.g. A ₁ ), the closing of the signal contact (10) of the extension via the normally open contact (5 ) the call relay (r _x to r ₃ ) energized call organ (I ₁ to I ₃ ) to switch off automatically by separating the contact (7) and to close a preparatory contact (8) for the final signal (S ₁ ) , which is then in Activity occurs when the dropping armature of the de-energized call relay (r _x to r _s ) closes its break contact (6) due to the interruption of the signal contact (io) of the intercom when the receiver (9 ) is attached. 3. A circuit according to claim 1 and 2, characterized in that when connecting branches (N ₁ ) to each other by means of plugs (ft, q) through interruption contacts (ri to 13) of the pawls (k _x to k ₃ ) the signal line (c) interrupted or the call relay (r _x to r _z ) is switched off. 1 sheet of drawings.