These telephones were made between 1956 and 1966 in Antwerp, Belgium at The Bell Telephone Works. They have a Zinc alloy case and a large brass carrying handle (folded down in pictures). Originally the phones were just a solid colour, black or white, but as the RTT prefers to recycle it's old equipment overseas, many of these phones found there way onto the second hand market and were either stripped back and coppered or re-sprayed and fitted with decals.
The Belgian state telephone company, RTT (Regie der Telegraaf en Telefoon/Regie de Telegraphe et Telephone) requested two suppliers, ATEA and BTMC, to come up with a standard telephone together. The new design appears to be based on a prewar design by ATEA, which got a US Patent in 1937 and was called the ATEAPHONE 50. The ATEAPHONE 50 case was made of Zinc Alloy (Zamac) or Bakelite and were supplied in black with a small number in white.
With some adaptations, such as the addition of the carrying handle, the new phone became the RTT 56 or as the suppliers called it the U56.
The RTT 56A was produced by ATEA whilst the RTT 56B was made by BTMC.
It is advisable NOT to fit an electronic transmitter to these phones, because of the circuit design they tend not to work.
The Belgium diagram DMT: 951-9 (Dated 1956) calls the telephone the YA-RTT. This diagram is exactly the same as the diagram SA15859A.
How to convert this telephone to work on PST
Conversion of telephone with diagram SA15859A-1 and AP209794
Conversion of telephone with ATEA diagram C20021
Conversion of telephone with ATEA Diagram C55027
Conversion of telephone with TMA diagram ST121
Conversion of telephone with RTT diagram ST141
Last revised: June 04, 2022