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Intermediate Wall Telephone

AD 100 (Originally the Telephone No. 325)
Intermediate Wall Telephone for 2-3 Earth Circuit Lines.

Local battery System.

Framework polished walnut, constructed to hold 2 cells RK 240 or RK 410 (Old Cat. No. 596 or 590).

Transmitter RC 120 on arm RC 500.

Receiver RD110 (No.546) with cord RS 4300 (No. 2030) suspended on switch-hook.

Generator RH 4120, 4-magnet, which will ring satisfactorily through the ringer and a line resistance of 15000 ohms.

Ringer 150 ohms resistance.

Press button which should be held down while ringing.

3-way Switch. The instrument is provided with a clip for holding papers on the desk.

This telephone is specially intended for use with 2 earth circuit lines L1 and L2.

The switch should be normally in the right or left hand position, and a signal given by one or other of the lines will reach the intermediate station in each case. The two lines L1 and L2 can communicate with each other independently of the position of the switch providing that the receiver at the intermediate station is on the switch-hook.

The intermediate station can communicate with either line, by moving the switch to the right or to the left respectively.

A third lineL3 can be connected to the intermediate station, and it can be called and communicated with when the switch is in the central position, and at the same time, lines L1 and L2 can communicate with each other.

If it is necessary for the third line L3 to call the intermediate station an extension bell RA 15 (Old Cat. No. 426) must be connected across the terminals J and L3 and should it be desirable to connect the third line to the lines L1 and L2, a switch AF 300 (Old Cat. No. 460) must be used. In the latter case, the extension bell RA 15 would not be required.

If the line L3 is in communication with the either line L1 or L2, the intermediate station can at the same time be in communication with the other line.

Height of Backboard: 720mm.
Width of Backboard: 215mm.

Weight: 7.7 kg.


In both the 1905, 1911 and 1912 L. M. Ericsson Telephone Catalogue

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Last revised: March 25, 2024