DF 220
Automatic table telephone for one local and one exchange line

The two lines can be connected to manual or automatic CB systems. The one line (Ll) may, for instance, be connected to a public telephone exchange and the other (L2) to a private exchange. The red button would then be for the public exchange and the white button for the private exchange.
Connection of the telephone to the one or the other of the lines is made by pressing the corresponding button. Conversations on one line cannot be over heard on the other. If during conversation over the public exchange line (Li) information is desired from a local source, the white button is pressed. The telephone is then connected to the local line (L2). The red button remains pressed and the public exchange line (LI) is held. ‘When the conversation with the local line is finished, by pressing again the red button, which has an extra bottom position, the white button is released, the telephone is disconnected from the local line and reconnected to the public exchange line. This telephone may be used as a wall set by means of a bracket RK 5010.

dial RG 112, dial cord RS 5062, condenser RI 260, 1 uF, microtelephone RE 1041 of black bakelite with removable capsule transmitter RC 4000 200, 200 ohm, and cord RS 5080, bell 1000 ohm for line L2, 2 press buttons (1 red and 1 white), case of black bakelite, bell box with 1000 ohm bell for line Ll, 2 condensers RI 260, 1 uF, instrument cord RS 9637, case of black enamelled sheet iron.

height 140 mm, width 233 mm, depth 175 mm, weight inc. bell box 3.6 kg.

Taken from the L. M. Ericsson Telephones and Signalling Material Catalogue No. 188 (1934)


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Last revised: August 06, 2002