Wall mounted bellset for internal use, generally found in customers premises.  Fixed to the wall with a 'T' shaped bracket, the same bracket used on 700 type wall phones.

Circuit diagram N550

Bellset No. 50A
Standard Bellset (2 x 500ohm bell ringers & capacitor). Supersedes Bell No. 59A.
Fitted with Bell No. 59C-1.

Bellset No. 50B
Bellset containing a Telephone, No. 746 circuit for use with Tele 713.  Supersedes Bellset No. 48

Bellset No. 50B (did not come originally with a cord)

Bellset No. 50C
Standard Bellset for new plan (PST - 2 x 2000ohm ringers & capacitor).

Bellset No. 50C (cover on) Bellset No. 50C (cover removed)

Fitted with Bell No. 59D-1.
Plastic cover in grey or ivory.

Bellset No. 50D
High impedance version wired for use with Telephone No. 713.

Bellset No. 50E
High Impedance Bellset with 3 Metre cord for use on PST, supersedes Bell Sets 50B & 50C for new supply and maintenance replacement, available on sale or rental terms (shown below).

Bell 50E, Denis Ferranti Ltd.

Bell Set 50E - S/1000/23/K/501724

Modifications which have not received appropriate approval must not be carried out as to do so would invalidate approval making connection unlawful. Bell Set 50E or 'Extension' line cord may be shortened without breaching approval.

For interior wall mounted use, supplied with plug ended cord for use with any phone socket.
Measures approx. 145mm x 145mm x 57mm, weight 470 grams. Comes with 2 wood screws, wallplugs and template for positioning screws. REN 1.

The Line cord of Bell Set 50E or 'Extension Tonecaller' may be cleated in place using Cleats Wiring 4C and if necessary be shortened (to a minimum length of 300mm) where bell/tone caller is to be fitted adjacent to phone socket.

Bell Set 50B (Low Impedance bell set for use with hard wired, series connected extension bell arrangements) are no longer available centrally on BT. Local stocks should only be used to maintain existing hard wired installations, when local stocks exhaust, faulty Bell Sets 50B should be maintenance replaced by Bell 50E and system converted to PST. Existing serviceable Bells Sets 50B and 50C may be used for internal shifts.

Taken from BT information

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Last revised: September 22, 2019