The world’s first electronic private branch telephone exchange (PBX), designed by Don Delanoy at Pye Telecommunications in 1956, has been donated to the Pye History Trust.

This prototype 10-line telephone exchange, thought to be one of the five original field trial models, will shortly be exhibited in the Pye Group exhibition, located in the Pye building at the Cambridge Museum of Technology, Cambridge.

This fascinating exhibit was kindly donated by James Delanoy, nephew of Don Delanoy, who said “My Uncle Don was a telecommunications pioneer with many patents to his name. I am therefore delighted that a world first in the ground-breaking telephone exchange that he invented has found its rightful place as an exhibit forming part of the Pye collection at the Cambridge Museum of Technology”.

The technology employed in this equipment was ingenious in that it used existing cold cathode switching valves and transistors rather than electro-mechanical components, and it paved the way for a family of telephone exchanges with 20-line and 100-line capability. This new electronic design replaced both manual and mechanical PBX exchange equipment. It had no moving parts and was therefore silent in its operation and far more reliable.

Don Delanoy was a genius in the communications field and highly respected in both the UK and wider international communications industry. He held 17 of the 32 Pye Telecommunications patents.