RECEIVER, INSETS

Used in most early Bakelite handsets. The coils had a total resistance of 80ohms.

The Mark 1 was introduced in 1931, the Mark 2 in 1941 and both were superseded by the Receiver, Inset No. 2P.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.

Mark 1 - Case1/SCA/29 - Aluminium alloy.
Mark 2 - Case 1/SCA/40 - Bakelite (Black).

Ensure that spring washers are fitted to the fixing screws.

See picture below for Pole Grinding in the factory.

Drawing - 62654 (Mark 1) and 62390 (Mark 2).

Specification - S59.

Used in later Bakelite handsets. The coils had a total resistance of 50ohms.

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.

Produced in alloy or plastic (see casing information below).

The Mark 2 and 3 body was coloured black when used for Red, Green or Black earpieces and coloured Ivory when used with Ivory earpieces.

Receiver, Inset No. 2P Mark 1 was introduced around  1942 and the Mark 3 in 1949.

Ensure that spring washers are fitted to the fixing screws.  The fixing screws are 3BA x 1" Cheese Head.

Mark 1 - Case 1/SFR/48 - Aluminum alloy.
Mark 2 - Case 1/SFR/51 - Phenolic resin (Black) and Stabilised Urea (Ivory).
Mark 3 - Case 1/SFR/54 - Aluminium alloy.

Drawing - 62911 (Mark 1, 2 and 3).

Specification - S207.

Technical description

Click here for pictures

Siemens Brothers part - Receiver No. 53C.

These are used in certain 700 type 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.

Marketing Instruction - TI B4 M0078

Used in Headsets and Trimphones.

24ohms coil resistance.

Drawing - 91020.

Specification - S506.

Produced by STC.

Used on Receiver, Head-gear No. 16U.

600ohms coil resistance.

Drawing - 91020.

Specification - S506.

Produced by STC.

Used in many 700 type telephones.  20 ohms resistance.

Diameter - 48mm.

Drawing - 90636.

Specification - S507.

Plessey part - N7201A2.

Click here for more information