Telephone Ring Generator - An all-electronic device to ring telephones authentically on stage. Simulates UK and USA ring cadences. Even rings Bell type phones. - http://www.precisiovision.freeuk.com/
Custom Electronic Industries, Inc. (CEI) - Product, ordering and general information regarding the Tele-Q RVG system designed to operate prop telephones for stage and screen. - http://tele-q.com