BNR was based at the Carling Campus in Ottawa, Ontario, Canada, with campuses at locations around the world, including Research Triangle Park, North Carolina; Richardson, Texas; Ann Arbor, Michigan; and Harlow and Maidenhead, United Kingdom.

Although George Stibitz had foreseen this evolution at AT&T in the 1930s, subsequent generations of engineers, prior to the 1970s, regarded the switch as a piece of hardware, best hard-wired, to handle the basic telephone call where two parties connect, speak and hang up.

Increasingly, telephone users wanted to conference call, forward, and record voice greetings, so common today.

Such features required more flexibility in the controller, leading to the development of computer-controlled switching machines, notably the Bell Labs − Western Electric 1ESS.

These early machines still had an analog, usually electromechanical switching matrix because the technology of the time did not permit the cost-effective dedication of a filter-codec to each subscriber.

BNR was, with Northern Telecom, a part owner of MicroSystems International a semiconductor manufacturer based in Kanata, outside Ottawa.

This was greatly influenced by the late 1970s success of the DEC VAX computer, a highly "elegant" and rather layered technology, realizable in a range of power.

The IEC layers were customer-specific, targeted towards Sprint, MCI, and a large group of small "United Carrier" companies that were subsequently swallowed up by Worldcom.

Once the IEC layer was established, customer-specific releases could occur quarterly, whereas Telecom and Base programming was for baked-in code that only had infrequent, maintenance updates.

BNR also had labs in Maidenhead, England, Montreal, Quebec, Edmonton, Alberta, Wollongong, Australia, and Tokyo, Japan; as well as Atlanta, Georgia and Ann Arbor, Michigan.