RECEIVER, INSETS

Used in most early Bakelite handsets. 80 ohms resistance.

Superseded by the Receiver, Inset No. 2P.

Always used with an Earpiece No. 18 and Diaphragm No. 12 (Stalloy - 52mm diameter).

Note the exposed coils in the centre of the receiver.

Ensure that spring washers are fitted to the fixing screws.

See picture below for Pole Grinding in the factory.

Drawing - 62390 (Mark 3).

Used in later Bakelite handsets. 50 ohms resistance.

Always used with an Earpiece No. 23 and Diaphragm No. 25 (Permandur - 52mm diameter).

Note the top of the receiver is enclosed, with a small air vent.

Receiver, Inset No. 2P Mark 3 was introduced around 1949.

Ensure that spring washers are fitted to the fixing screws.

Siemens Brothers code - Receiver No. 53C.

Drawing - 62911.

Used in 700 handsets.  Introduced as an aid to those who wore hearing aids.  The receiver had a coil of wire wound around the outside and this would interact, inductively, with a hearing aid that was switched to the 'T' setting.

The No. 1/3T was introduced in 1980.

The 2/3T was used in Handsets No. 3, 7, 11A and 14A and is shown pictured to the right.

Drawings - 93888 and 93889.

Specification - S1371.

Used in Headsets and Trimphones.

20 ohms resistance.

Drawing - 91020

Specification - S506.

Used on Receiver, Head-gear No. 16.

600 ohms resistance.

Used in many 700 type telephones.  20 ohms resistance.

Later Receiver Insert No. 4's comprised of a No. 3T inserted into a plastic housing which resembled the No.4 - dimension wise.

Construction details

Drawing - 90636.

Specification - S507.