Wooden boxed magneto bell with two external gongs used with C.B. table telephones.

This Bellset was originally called the "Bellset, Magneto, CB".

The early cases had a small key lock on the front door, but this was removed and a spring loaded captive screw fitted to the left hand side of the casing.

It was fitted with a 2uf Capacitor, a 1000 ohm Ringer (comprises of two 500ohm coils) and a two winding Induction Coil (primary coil is 17ohms and secondary coil is 26ohms).

Generally used with Telephones No. 2, No. 10 and No. 150 etc (Candlestick telephones).

The Bellset was also made in a number of iterations - please see table below.  Many were adopted from the sale of the National Telephone Company to the GPO.

The wooden casing is called a Case No. 1 and could be constructed of American Walnut, Black Chuglam, Pyinma, Halou, Tasmanian Myrtle or African Mahogany.

Bellset No. 1 with Bias Spring, was also available for Telephones No. 76, No. 82 and No. 124.  This variant used a "Bell No. 1A, unmounted, with Bias Spring" as the ringing mechanism.  Probably marked "BS" on the rear of the case.

Click here for more information on Bias Springs.

Do not confuse this Bellset with a Bell No. 1A, which has a smaller case and only comprises of a bell ringer and two gongs.

This Bellset was universally used by the GPO with table telephones and recovered Bellsets were refurbished and reused.  In some cases they were made into wall telephones.

By 1946 this Bellset was superseded by Bellset No. 25.

Bellset Includes:-
1 x Bell No. 1A, Unmounted.
x Bell-gong No. 2, Oxidized.
1 x Bell-gong No. 2A, Oxidised.
x Washers, Locking 1-2BA.
x Capacitor, MC No. 102.
x Coil, Induction No. 14.
x Screws for fixing.

Bellset No. 1 Mark 235

Identifying a Bellset No. 1



Includes Blank 234/5 NT10 NT12 NT19
Bells No. 1, unmounted 1 1 - - -
Bells No. 11, unmounted - - 1 1 -
Bells NT No. 1002A - - - - 1
Coils Induction No. 3 or 14 - - 1 1 1
Coils Induction No. 4 or 14 1 1 - - -
Condensers MC No. 2 or 30 (4⅜" x 1⅝" x 1⅝") 1 - - 1 1
Condensers MC No. 3 or 30 (4⅜" x 1⅝" x 1⅝") - 1 - - -
Condensers MC No. 6 - - 1 - -
Bell Gong No. 2 - - 2 2 -
Bell Gong No. 3 (Aluminium) - - 2 2 -

The above was taken from the GPO Rate Book (1928)

Wiring Diagrams - LD 38 (Mark NT19), N501 (1919) and N501 (1929).

Drawing - Bellset - 1751 (Mark 235).
Drawing - Case - 7276.

Ericsson made some of these Bellsets, their model N3090.

GEC made some of these Bellsets, their model K8175 with diagram numbered KS6724.

UK Military number - YA2494.

Adjustment of Magneto bells

Click here for the difference between a Bell and a Bellset

Pictures showing Bellset No. 1 with the capacitor (bottom of left hand picture)
and the Coil Induction No. 4 (above the capacitor)


Bellset No. 1 Mark 234
The capacitor is mounted on the Bellset door.
The wiring for the capacitor is connected to the main body wiring through the hinges.
The Bell ringer is fitted with a bias spring.
Made by Siemens Brothers their Number Q2217


Picture of Bellset No. 1 Mark 235 with Coil Induction No. 18
This Bellset has most probably been factory refurbished by the GPO as the Induction coil is of the
later type and the terminals are on the base, instead of on the bottom of the front casing.
Note the second paster diagram, pasted over the original paster


Early Bellset No. 1

These Bellsets below are early examples, they can be GPO or NT examples.
The capacitor in both styles, fits inside the base.

These were probably manufactured at the W.E. factory by B.T.M.C. of Antwerp

Front View Internal View


Front view showing diagram and latch
Close up of terminals
Wiring diagram

Bellset No. 1 with door lock

Front view of the case and to the left is the capacitor which has been removed from the base.
View of the base showing where the capacitor fitted.  The lower fixing clip is missing.
Inside the Bellset showing Induction coil and bell ringer



Bellset No. 1 with door lock
Ericsson (1909)


An unusual layout
The terminals are mounted on a projection
Unusually marked inside the casing - E 09 (Ericsson made in 1909)


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Last revised: October 03, 2023