SWEDISH TELEPHONE No. 


AP 100
Subscriber’s amplifying set


This set is composed of a two-way amplifier and telephone instrument, both fitted in one cover. The exterior of the set is similar to that of the standard Ericsson. It is designed for use by persons with poor hearing and also for use with lines having low transmission properties. For this latter reason amplification of outgoing speech has also been provided for. The maximum amplification of incoming speech is about 2.3 neper (20 db) and this amplification can be regulated by means of a potentiometer, the knob of which is placed in the bottom right hand corner of the set. The input level should not, however, exceed about 1.3 neper (11.5 db), to avoid distortion. For outgoing speech the amplification is usually adjusted so that zero level is obtained at the near end of the line.

For lines giving poor transmission the output can be adjusted to a certain positive level by altering the tappings of a transformer. In this manner the amplification can be regulated 0.8 neper (7 db) in steps of 0.2 neper (1.75 db). The highest possible output level will consequently be + 0.8 neper (7 db). AP 100 is connected as an extension to an ordinary telephone instrument. Calls can then be carried on from the main instrument which is connected as usual, or from the amplifier, which is automatically connected when its handset is lifted. For calling, the main instrument must be used; this instrument also receives the incoming signals.
AP 100 can be connected as extension instrument to any system. When connected to an automatic system the handset of the amplifier, from which a conversation is to be carried on after a call has been made from the main instrument, must be lifted before the handset of the main instrument is replaced.
The set requires a battery RK 220 of 1.5 V and a battery RK 810 of 60 V; these two batteries may be fitted in a battery case RK 2312.

Parts:
dial blank RG 5000 covering the hole for the dial, rnicrotelephone RE 1060 of black bakelite with removable capsule transmitter RC 4000/40, 40 ohm, and cord RS 6162, cover of black-enamelled sheet iron, knob for adjustment of the amplification, bell box with instrument cord RS 9701, two Marconi valves L 11.

Dimensions:
height 140 mm, width 233 mm, depth 175 mm, weight 3 kg inc. bell box.

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

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Last revised: August 11, 2002