gec.gif (1164 bytes)GEC MURAPHONE
ST2301 - ST2316, ST2401 - ST2416, ST2501 - ST2516, ST2601 - ST2616 and TEL/1M, TEL/2M, TEL/6M & TEL/8M


The original part numbers for the Muraphone was three digit numbers (GEC Magazine) but in 1946 the phones were re-numbered ST 23xx, ST 24xx, ST 25xx and ST 26xx series and again in1955 GEC decided to renumber all their telephones with the prefix TEL.  Please see the table below and also follow the link called "click here for general information".

Click here for general information on the Muraphone

Click here for the Muraphone K - updated Muraphone with new style handset and circuitry

Click here for information on how to convert your Muraphone to Plug and Socket

Click here for the Muraphone circuit diagram

The picture shown to the right is the earlier Muraphone, which easily identifiable by the spittoon mouthpiece.  The later version, known as the Muraphone K, has the modern curved handset, without the spittoon mouthpiece.

THE GEC MURAPHONE

Application
A wall-mounting telephone for use with all automatic or C.B. manual systems. Designed in two slightly-different types, one for the usual public service systems and the other for hotels, service flats and passenger vessels.

Construction
The case is a plastic moulding, in either black or a selected colour. It is shaped to form a cradle for the receiver and a housing for the transmitter, so that the handset is securely held in a vertical position. The front surface is the correct width to accommodate a dial, and the circular motif is repeated at the sides of the moulding by concentric segments. These are provided with sound-outlet apertures for the bell or buzzer with which the Muraphone may be fitted.

The cradle switch is extremely positive in action, and is operated by a lever on which the receiver rests when the handset is in position. Rollers, attached to the switch lever, actuate the switch springs. These are provided with twin contacts, and the leverage obtainable allows contact pressures to be greater than in plunger-type cradle-switches.

The G.E.C. dial is the British Post Office standard, with stainless steel fingerplate. It is fixed to a special support, so that the case can be removed entirely. The C.B. Muraphone for public systems is convertible to automatic working by the removal of the dial dummy, replacement by a dial, and connexion of a dial cord.

The terminal strip, mounted at the lower end of the unit, terminates line wires, handset cord and dial cord on screw terminals, which are separated by moulded insulators to prevent surface leakage. A tight-fitting rubber bush anchors the handset cord to the terminal strip. This arrangement relieves the conductors of the strain from a direct pull, seals the point of entry, and allows the cord maximum flexibility without the possibility of frayed braiding.

For Ships, Hotels, Flats, etc.
For the model specially designed for ships, hotels and flats the subdued note of the buzzer is generally preferred to the louder ring of the bell, and plunger-type terminals replace the screw-type for line wires. Line wiring can be concealed in the decorations and terminated on a small connexion block, which is provided with sockets to take the plunger terminals when the Muraphone is fixed to the wall. This type of Muraphone can thus be plugged in to existing wiring as required.

Because the systems for which it is designed are not likely to change from manual to automatic operation, the C.B. version is not designed to allow the quick fitting of a dial.

The B.P.O. standard inset-type transmitter and receiver are included in a high-efficiency speech circuit which gives the intelligibility that results from the maximum suppression of sidetone.

A spark-quench circuit protects the dial impulse springs.

If required, a suppression circuit can be included to prevent interference with nearby radio receivers during dialling.

Tropical Models
The tropical Muraphone incorporates special features which are the result of long experience

  • A shunt is connected across the transmitter to minimise the minute arcing that tends to occur at the granules and electrodes as the cradle switch operates the accelerated tendency towards frying often shown by transmitters in the tropics is thereby offset. The effect of any increase in transmitter resistance upon line circuit conditions is also minimised by the shunt. The loss in volume efficiency is very small and is partly cancelled by reduction of sidetone, the net result being a difference of only 1 db.
     
  • Apertures in the case are covered with fine wire gauze to prevent the ingress of insects.
     
  • Metal parts and all wiring are specially finished and treated to resist the effects of high-humidity atmospheres.
     
  • Cradle-switch springs are covered with varnish to maintain insulation resistance.
     
  • Flexible conductors are V.I.R. covered and braided overall.
     
  • All coils are specially treated to render them impervious to damp, heat, and sudden variations of temperature.
     
  • For very dusty atmospheres, a bakelite cover can be fitted to the back of the dial, giving complete enclosure of the mechanism.

Colours
The standard colour is Black, but enquiries are invited for the telephone in Ivory, Jade Green or Chinese Red, with cords finished to match.

Connexions
Connexion Block for line wiring for Muraphones with plunger terminals - Cat. No. CBI 101.

Dimensions
Height, 9.3 (25 cms) 
Width, 5.3 (14 cms) 
Depth (over handset), 5.75 (15 cms)

Weight
Average of all models, 4.25 lbs. (l.9 kgs.)

Taken from the Catalogue Leaflet No. STL.7

 

Pre 1955 Catalogue Numbers

  STANDARD TROPICAL
C.B. AUTO C.B. AUTO
Screw Terminals Plunger Terminals Screw Terminals Plunger Terminals Screw Terminals Plunger Terminals Screw Terminals Plunger Terminals
With Bell Black ST2301 ST2305 ST2501 ST2505 ST2401 ST2405 ST260l ST2605
Ivory ST2302 ST2306 ST2502 ST2506 ST2402 ST2406 ST2602 ST2606
Green ST2303 ST2307 ST2503 ST2507 ST2403 ST2407 ST2603 ST2607
Red ST2304 ST2308 ST2504 ST2508 ST2404 ST2408 ST2604 ST2608
With Buzzer Black ST2309 ST2313 ST2509 ST2513 ST2409 ST2413 ST2609 ST2613
Ivory ST2310 ST2314 ST2510 ST2514 ST2410 ST2414 ST2610 ST2614
Green ST2311 ST2315 ST2511 ST2515 ST2411 ST2415 ST2611 ST2615
Red ST2312 ST2316 ST2512 ST2516 ST2412 ST2416 ST2612 ST2616

 

1955 CATALOGUE NUMBER CONVERSION TABLE

Obsolete Part Number Description Revised Part Number
ST2301 C.B. Bell, Screw Terminals, Std TEL/1M/CWS
ST2309 C.B. Buzzer, Screw Terminals, Std TEL/1M/CWS/1
ST2401 C.B. Bell, Screw Terminals, Tropical TEL/2M/CWT
ST2405 C.B. Ships, Bell, Plunger Terminals, Tropical TEL/6M/CWT
ST2409 C.B. Buzzer, Screw Terminals, Tropical TEL/2M/CWT/1
ST2413 C.B. Ships, Buzzer, Plunger Terminals, Tropical TEL/6M/CWT/1
ST2417 C.B. Bell, Plunger Terminals, Tropical TEL/8M/CWT
ST2421 C.B. Buzzer, Plunger Terminals, Tropical TEL/8M/CWT/1
ST2501 Automatic, Bell, Screw Terminals, Std TEL/1M/AWS
ST2509 Automatic, Buzzer, Screw Terminals, Std TEL/1M/AWS/1
ST2601 Automatic, Bell, Screw Terminals, Tropical TEL/2M/AWT
ST2605 Automatic, Bell, Plunger Terminals, Tropical TEL/8M/AWT
ST2609 Automatic, Buzzer, Screw Terminals, Tropical TEL/2M/AWT/1
ST2613 Automatic, Buzzer, Plunger Terminals, Tropical TEL/8M/AWT/1

 


ADDITIONAL INFORMATION AND PICTURES

These are pictures are of the original Muraphone - easily identified by the spittoon mouthpiece

ST2301 - CB version ST2502 - Auto version
   
ST2510 Internal view ST2510 External view
   
Early picture of the terminal block connector model - note no screw terminals for L1, L2 or E, as the block connects to the rear Same telephone shown to the left, but with the dial removed to expose all components that are mounted on the base plate

 

ST2404

Front view.  The grey cord and terminal block were not originally supllied

 

Front view showing the earlier spittoon style handset

 

View of base plate showing original feet
The wall fixing screws went through the centre of the feet

 

 

TEL/1M/AWS



TEL/2M/CWT



In the picture above, the feet are fixed by screws - it is thought that the feet on this phone have been replaced.

 

 

 
 
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Last revised: November 30, 2015

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