This is a one-piece convertible type telephone so arranged that it can be readily
altered to work to all kinds of exchange systems, such as, for example, the following:-
It therefore provides the most economical proposition, especially for telephone operating concerns, because it does not become redundant with a change of system.
Circuit alterations are readily made internally and the only additional apparatus required is an induction coil for C.B. conditions and a dial for automatic.
Micro-telephone cord N4021
Diagrams showing the connections for the above systems are provided with each telephone, and on application customers will be supplied with a booklet containing a photograph as illustration above, diagrams, drawings and lists giving the codes of parts used in the instrument, and which will be found. invaluable for reference or for ordering spare parts.
Taken from the Ericsson catalogue, edition No. 49
Last revised: October 04, 2019