John Callas studied electrical & electronic engineering at Athens University, graduating in 1974. He worked for ERT (Hellenic Radio & TV) as a sound recordist and cameraman between 1973 and 1976 in the news department and travelled all over the world. In 1977 he moved to England, working as a 16mm cameraman for the BBC.

Between 1981 and 1992, John held positions with  Cadbury-Schweppes as an AV manager, Midwest Comms as a design engineer for satellite up-link vehicles and Omega Productions as a broadcast engineer for Greek TV channels.  With the advent of cable TV, he joined Birmingham Cable as a headend and CATV engineering manager, rising to Principal Engineer (after the Telewest acquisition) in charge of Telewest’s headend and hub infrastructure design. 

John retired from Virgin Media at the end of 2016 and is currently working as a consultant in CATV & 5G mobile infrastructure.