Private automatic switchboards for 10 - 22 lines
The parts of the switchboards - relays, selectors, relay pole changer and fuses - are mounted on a black enamelled iron frame. The switchboards have bracket feet at the bottom for attaching to the floor or a wall bracket.

If the switchboards are to be fixed direct to a wall then the bracket feet are removed to one side and fixed to the wall so that the switchboard stands at right angles to the wall.

One or two storage batteries of 24 Volts are required for a switchboard. Charging equipment to suit local conditions can be supplied.

The series of call numbers are:
for 10 numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 0;
for 12 numbers: 1, 2, 3, 4, 5, 6, 7, 8, 91, 92. 93, 94;
for 22 numbers: 1, 2, 3, 4, 5, 6, 7, 8, 91, 92, 93, 94, 95, 96, 97, 98, 991, 992, 993, 994, 995, 996.

Dimensions:
For up to 12 lines: height 485mm, width 403mm, depth 180mm.
For 13 - 22 lines: height 743mm, width 540mm, depth 180mm.

Telephones of type DE should be used in connection with these switchboards.

OL 3510 - Floor mounted	OL 3510 - Wall mounted	OL 3522

Switchboards with exchange line facilities
These automatic switchboards can be connected to a public telephone exchange by one or more lines. The type of switchboard to be used depends on the number of exchange and extension lines required.

The switchboard used under these conditions should be equipped with exchange line relay sets.

If desired, any of the DE telephones connected to OL 3530 - OL 3578 and can be prevented from calling the public exchange by means of a simple alteration of the wiring.

Telephones of the following types should be used: telephones DF 310, one for each exchange line, for those stations which have also to receive and distribute calls from the public exchange; telephones DF for the other extensions. These stations have communication with the public exchange over the sets DF 310 (incoming calls) or by dialling the digit 0 (outgoing calls). 

Under these conditions the following types of switchboards should be used.

If it is desirable to receive and distribute all incoming calls from the public exchange over one telephone, a telephone DG 101 should be used.

This telephone is also equipped for one ordinary extension line from the OL switchboard. One bell box DC 1021 should be connected to this extension line. Telephones DE are suitable for the other extensions. These stations have communication with the public exchange over the set DG 101 (incoming calls) or by dialling the digit 0 (outgoing calls).

U n d e r these conditions the following types of switchboards should be used.

Taken from the L. M. Ericsson Catalogue No. 188 (1934)

 

Last revised: March 29, 2024