DAH 9001 and DAH 9002 (replaces AP 100 and AP 110)

DAH 9001
This device contains a two-way amplifier. It is intended for use by people with disabilities hearing ability and also on lines with poor transmission properties. For the latter purpose the device also amplifies the outgoing speech. Maximum the gain for incoming speech is about 2.3 neper and the gain can be regulated with a potentiometer, the control knob being located in the lower right corner. For avoidance of distortion the incoming level should not be higher than -1.3 nep. For outgoing numbers is usually set zero level. For cables with poor transmission properties creates, the device can be adjusted to give a certain positive level by switching the microphone transformer's grid outlet. In this way, the gain can be regulated 0.8 neper in steps of 0.2 neper. Highest possible output level is thus + 0.8 neper.

The device is connected as a side device to a regular one telephone set. Calls can thus be made from the main the device, which is connected in the usual way, or from the amplifier, which is automatically switched on, when its handset was lifted off. When called was used the main unit, which also receives incoming ringtones.

This device can be connected as a side device to which any system. In the case of automatic systems, after one call, before starting the call on the repeater, its handset is lifted off before the main unit's microphone is hung up.

This device has a black Bakelite cover. The telephone requires a dry cell BKA 1004 of 1.5 Volts and a battery BKA 1501 at 60 Volts. Suitable battery box for these are the BKY 1004.

Parts:
Microphone RLF 1024 made of black Bakelite with microphone capsule RLA 1004, 40ohms, and string TRS 1401, 1250mm.
Marconi tube L 11 (two).
Transformer REK 10201.
Transformer REK 10202,
Transformer REK 10203.
Capacitor RKA7121, 1+0.12uF
Line cord TRS 1101, 1300 mm.
Wall bracket NEF 1101.

Dimensions:
Height 139mm, width 233mm, depth 178mm.

Weight 3.0 kg.

DAH 9002
This telephone is specifically intended for connection to the Swedish national telephone network. It is similar to DAH9001 and contains essentially the same parts as this one. Permission to connect must be obtained in each particular case from K. Telegrafstyrelsen, which is handled by Telefonaktiebolaget L.M. Ericsson.

Taken from the L. M. Ericsson Catalogue No. 610 (1939) - Swedish Translation

Last revised: March 25, 2024