TMC SOUND POWERED
TELEPHONES


SOUND POWERED TELEPHONES

These tough long-life TMC telephones are completely self-contained - they need no battery supply

TMC sound-powered (batteryless) telephones are sturdy instruments capable of giving long service in locations where telephones are exposed to the toughest conditions.
Originally developed by the Marine Department of Telephone Manufacturing Company Limited for use aboard ship, their design and construction have proved them ideally suitable for a variety of applications under equally exacting conditions ashore. Telephones of these types have been supplied extensively by TMC for use in mines, tunnel excavations, oilfields, shipyards and building sites.

As TMC sound-powered telephones are self-energizing and completely independent of battery or mains supplies they are easily transportable, simple to operate, require the minimum attention and can be installed immediately in any location.

Bulkhead Telephone Type L50 & L50A (shown to the right)
L50 comprises a sound-powered handset, hand operated calling generator and a howler calling unit in a non-corrodible cast aluminium alloy weatherproof case with a pleasing grey hammered finish. It is designed for use where a really robust type of telephone is required.
L50A as type L50, but fitted with a switch operated by a handset cradle. It is intended for connection as an outstation with intercommunication type telephones L76 and L77. For use in extremely noisy situations these bulkhead telephones can be fitted with an extra receiver for an additional charge.

L50A (taken from undated document)
as type L50, but fitted with a switch operated by a handset cradle. It is intended for connection as an outstation with intercommunication type telephones L70, L71, L76 and L77. A 4-core cable is required for connection.

L50C (taken from undated document)
Is similar to type L50 but includes an indicting lamp, making it suitable for use where more than one instrument is installed at the same location. The lamp lighting while the generator at the calling station is operated to indicate the instrument being called.

Both L50 and L50C telephones are suitable for use as direct working pairs, or alternatively for working with each other or types L74, L75 and L79. A 3-core cable is required for connection.

L50D (taken from undated document)
Is similar to type L50A, but connected internally to permit working over 2-wires. The type is suitable for use as direct working pairs, or for working with instrument L51.

L50E (taken from undated document)
Also similar to type L50A, but connected internally to permit working over 3-wires. It is primarily for use where parallel working of up to a maximum of six telephones is required. (A system of `code ringing' is necessary for this type of installation).
For use in extremely noisy situations any of these bulkhead telephones can be fitted with an extra receiver for an additional charge.
 

Portable Telephone L51
The sheet-metal case is fitted with a webbing carrying strap and contains a sound-powered handset, high frequency calling generator and thumb-screw line connection terminals. Incoming calling signals are received as a 'hoot on the sound-powered insert units in the handset.

Portable Telephone L51 (taken from undated document)
This instrument is ideal for temporary installation in railway marshalling yards, mines rescue operations or building sites, etc. The sheet-metal case is fitted with a webbing carrying strap and contains a sound-powered handset, high frequency calling generator and thumbscrew line connection terminals. Incoming calling signals are received as a `hoot' on the sound-powered insert units in the handset.
Two wires are required for connection between instruments.
 

 

Bulkhead Telephone L64
This weatherproof telephone has a hand telephone set with a spiral cord and is totally enclosed by a hinged snap-shut lid when not in use. It has a ferrous alloy case.
It was specially designed for the National Coal Board using a separate safe signalling system supplied by N.C.B.




Intercommunication Cabin Bulkhead Telephone L70 (taken from undated document)
This telephone is intended for use where communication is required to two or more outstations and comprises a sound-powered handset, hand operated calling generator, buzzer and a 12-position switch providing selective calling and speaking to a maximum of eleven outstations. The smart black bakelite case makes it suitable for use in ship's cabins, etc., and it can be interconnected to other telephones of the same type or to types 30A, L71, L72, L73, L76, L77 and L78.

The number of conductors between telephones is dependent upon the system required and, if you wish, TMC will advise you of the correct number needed for your installation.

Intercommunication Cabin - Telephone for Desk Use L.71 (taken from undated document)
This telephone possesses exactly the same facilities as the L70 and has a similar finish. It is for desk use.

Single Way Cabin Bulkhead Telephone L72 (taken from undated document)
Is similar to type L74, but fitted with a switch operated by a handset cradle. It is intended for connection as an outstation with intercommunication type telephones L70, L71, L76 and L77. A 4-core cable is required for connection.

Single Way Cabin Bulkhead Telephone L73 (taken from undated document)
As L75 but fitted with a switch operated by a handset cradle and suitable for connection as an outstation with intercommunication type telephones L70,

Single Way Cabin Bulkhead Telephone L74  (taken from undated document)
Comprises a sound-powered handset, hand operated calling generator and buzzer - and, like the L70, it has a smart black bakelite case. This type is suitable for use as direct working pairs, or alternatively for working with instruments L50, L50C, L75 and L79. A 3-core cable is required for connection.

Single Way Cabin Bulkhead Telephone L75 (taken from undated document)
L75comprises a sound-powered handset, hand operated calling generator and buzzer in a black bakelite case and is suitable for use as direct working pairs, or alternatively for working with instruments L50, L50C, L74 and L79. A 3-core cable is required for connection.
L71, L76 and L77. A 4-core cable is required for connection.

Intercommunication Bulkhead Telephone L76
This telephone is suitable for use where communication is required to two or more outstations, and comprises a sound-powered handset, hand operated calling generator, howler calling unit and a 12-position switch providing selective calling and speaking to a maximum of eleven outstations.
The non-corrodible, cast aluminium-alloy weatherproof case with grey hammered finish makes it a really robust instrument and it is intended for connecting to other telephones of the same type or to types L50A, L77 & L78.

Intercommunication Bulkhead Telephone L76 (taken from undated document)
This telephone is suitable for use where communication is required to two or more outstations, and comprises a sound-powered handset, hand operated calling generator, howler calling unit and a 12-position switch providing selective calling and speaking to a maximum of eleven outstations.
The non-corrodible, cast aluminium-alloy weatherproof case with grey hammered finish makes it a really robust instrument and it is intended for connecting to other telephones of the same type or to types L50A, L70, L71, L72, L73, L77 and L78.
The number of conductors between telephones is dependent upon the system required and, if you wish, TMC will advise you on the number required for your installation. For use in extremely noisy situations an extra receiver can be fitted at an additional charge.

Intercommunication Bulkhead Telephone for Portable & Bulkhead mounting L77
L77 comprises a sound-powered handset, hand operated calling generator, howler calling unit and a 12-position switch providing selective calling and speaking to a maximum of eleven outstations. The non-corrodible, cast aluminium-alloy weatherproof case with snap-shut lid makes it suitable for the most exposed positions. It is intended for connecting to other telephones of the same type or to types L50A, L76 & L78.

Intercommunication Bulkhead Telephone for Portable & Bulkhead mounting L77 (taken from undated document)
L77comprises a sound-powered handset, hand operated calling generator, howler calling unit and a 12-position switch providing selective calling and speaking to a maximum of eleven outstations. The non-corrodible, cast aluminium-alloy weatherproof case with snap-shut lid makes it suitable for the most exposed positions and all components are mounted on the inner cover, which is removable as a unit from the case, permitting easy access for maintenance purposes. It is intended for connecting to other telephones of the same type or to types L50A, L70, L71, L72, L73, L76, and L78.

Intercommunication Bulkhead Telephone for Portable & Bulkhead mounting L77A (taken from undated document)
Is a portable version of type L77 supplied with 8ft. C.T.S. cable, with W.T. plug and socket, hooks for deck rails and a brass carrying handle.

Single Line Hood Telephone for Portable and Bulkhead mounting L78
As type L79 but fitted with a switch operated by a handset cradle. It is intended for connection as an outstation with intercommunication type telephones L76 & L77.

Single Line Hood Telephone for Portable and Bulkhead mounting L78 (taken from undated document)
As type L79 but fitted with a switch operated by a handset cradle. It is intended for connection as an outstation with intercommunication type telephones L70, L71, L76 and L77. A 4-core cable is required for connection.

Single Line Hood Telephone for Portable and Bulkhead mounting L78A (taken from undated document)
Is a portable version of type L78 supplied with 8ft. 4-core C.T.S. cable, 4-pin W.T. plug and socket, hooks for deck rails and a brass carrying handle.

Single Line Hood Telephone for Portable and Bulkhead mounting L79
Is a single line version of type L77 and is suitable for use as direct working pairs, or alternatively for working with L50. A 3-core cable is required for connection.

Single Line Hood Telephone for Portable and Bulkhead mounting L79 (taken from undated document)
Is a single line version of type L77 and is suitable for use as direct working pairs, or alternatively for working with instruments L50, L50C, L74 and L75. A 3-core cable is required for connection. If required for extremely noisy situations an extra receiver can be fitted at an additional charge.

Single Line Hood Telephone for Portable and Bulkhead mounting L79A (taken from undated document)
Is a portable version of type L79 supplied with 8ft. 3-core C.T.S. cable, 3-pin W.T. plug and socket, hooks for deck rails and a brass carrying handle.

Accessories
High Frequency Relay Type L87

The high frequency relay has been designed to operate in conjunction with TMC sound-powered instruments in locations where external noise necessitates a loud-sounding bell, re-entrant horn or rotating beacon to supplement the howler incorporated within the telephone itself.

Loud Sounding Bell
For systems where the call unit of telephone is not sufficient to overcome the level of background noise. Operates in conjunction with H.F. relay; a.c. or d.c. Various sizes available.

Rotating Beacon
For the location which has a high level of background noise, the rotating beacon can be fitted to give a visual calling signal. For ships' engine rooms, workshops, etc.

Re-entrant Horn
Type 'A' Re-entrant Horn. Fitted with a TMC Sound-Powered Unit, this is a medium sized horn giving a loud calling signal in situations with a high ambient noise level. Either standard mounting brackets or gimbal and spigot.

 
Dimensions of TMC Sound-Powered Telephones
 
Model Width Height Depth Weight
L50 & L50A 7.5 in. (19 cm.) 11.5 in. (29 cm.) 7.5 in. (19 cm.) 13 lb. (5.9 kg.)
L51 5 in. (12.7 cm.) 5.5 in. (14 cm.) 11.25 in. (26 cm.) 8.75 lb. (4 kg.)
L64 9.75 in. (24.5 cm.) 13.1 in. (33.5 cm.) 6.5 in. (16.5 cm.) 28 lb. (12.7 kg.)
L76 8.5 in.(21.6 cm.) 11.5 in. (29.2 cm.) 8 in. (20.3 cm.) 15 lb. (6.8 kg.)
L77 10.5 in. (26.7 cm.) 16.5 in. (41.9 cm.) 7.5 in. (19 cm.) 21.5 lb. (9.8 kg.)
L78 & L79 10.5 in. (26.7 cm.) 16.5 in. (41.9 cm.) 7.5 in. (19 cm.) 21 lb. (9.5 kg.)


TMC sound-powered telephones comply with Ministry of Fuel and Power Certificates covering up to group II of intrinsically safe requirements.


Take from the TMC Leaflet S.Pow/TE/CP/2M/1266 (1966)

 


Last revised: 11 November, 2010

FM2