Dictograph loudspeaking "master" house-telephone unit, c.1940

The office intercom consisted of this 'master station' and several substations. It enabled a supervisor to speak to any assistant or set up a conference call.

Dictograph Telephones Ltd's office telephone and intercom systems were first patented in the USA in 1907 and soon were introduced internationally and were expanded to include PAXs, wireless sets and speakers, and military communications equipment between 1907 and the First World War.

Dictograph products were used internationally but were the longest use in the UK, which included a similar pattern to the US ones as well as local variations. Manufacturing for the British and colonial markets was partly undertaken by Autophone, a subsidiary of the British Home Office Telephone Company, from their factory in Wimbledon, south London. Another factory at Croydon supplied phones, but dates are unknown. In the 1950s, Autophone was an Original Equipment Manufacturer (OEM) company that sold only to their sister company British Home & Office Telephone Company (BHOTCo), Birmingham Telephone Company (BTC), Dictograph Telephones Ltd, Shipton and no doubt to others as well.

Autophone used many imported parts in their construction, mostly brought in once again from H Fuld GMBH. Handsets were branded Dictograph. Fuld later became Telefonbau und Normalzeit (T&N), and some very late Dictographs had T&N-branded handsets instead. The British part of the construction was mostly the cabinet woodwork and the wiring. Final assembly was eventually moved to a factory in Coventry.