|Receivers, Bell No. 4A
has no permanent magnet and the coil is of 60ohms resistance. It
called an Electro-magnetic receiver.
Used on Telephones No's 55, 55B, 72, 72A and 98.
American make includes:-
1 x Diaphragm No. 9.
1 x Earpiece No. 4.
Mark 234 includes:-
1 x Diaphragm No. 12.
1 x Earpiece No. 2.
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