Deltaphone

The Deltaphone was a later Trimphone variant.

The Trimphone is a model of telephone designed in the early 1960s in the UK, the first prototypes appearing in 1965. It was positioned as a more fashionable alternative to the standard telephones available from the General Post Office (GPO), the nationalised predecessor to British Telecom. The name is an acronym standing for Tone Ring Illuminator Model, referring to the novel electronic ringer and the illuminated dial. The luminous dial or betalight contained the mildly radioactive element tritium, which later caused some concern about safety. In June 1991, the United Kingdom Atomic Energy Authority at Harwell was fined £3,000 by Wantage Magistrates Court for accumulating radioactive waste, having collected several thousand Trimphone luminous dials in a skip.