GPO 312L telephone Designer (Person) Heiberg, Jean Bjerknes, Johan Christian Designer (Organisation) Ericsson GPO Manufacturer Siemens Manufactured for GPO Date 1954
Viscount telephone Designer (Person) Carr, Peter Howett, Fred Hiner, Peter Designer (Organisation) STC Manufacturer STC Manufactured for BT Date 1981 - 1989 (circa)