For much of its early history, Bell Canada was an operating division of Bell in the USA. Development and manufacturing of their various telephony products generally took place in the US. Soon thereafter, due to cross-border duty issues, manufacturing was migrated to Canada at their Northern Electric subsidiary (later renamed Northern Electric) which was the Canadian sister company of Western Electric in the USA. For many years Northern Electric was used as Bell Canada's R&D arm, although most telephony designs were created at Bell Labs in the US (which maintained IP ownership).

In 1949, the United States Justice department forced AT&T (nee Bell) to divest itself of its Western Electric subsidiary. As a result of this legal action, Western Electric sold its shares in Northern Electric to Bell Canada.  In 1957, Northern Electric started its own research and development labs in Ontario. Two years later, Northern Electric created the Northern Electric Research and Development Laboratories in Ottawa. In 1971, Bell Canada and Northern Electric combined their R&D organizations and formed Bell-Northern Research.

In 1964 Bell Canada acquired 100 percent of Northern Electric. Then, through public stock offerings which commenced in 1973, Bell sold partial ownership but maintained majority control. As a result, Northern had a preferred supplier agreement with Bell Canada which was aggressively leveraged to establish a very strong market share position in the Canadian Market. Similar agreements were implemented in each province with the provincially owned telco’s  BCTel, AGT, SaskTel, etc.  

Until divestiture and the creation of the Regional Bell Operating Companies (RBOCs), AT&T was in a very similar position in the USA.  They controlled the local and LD communications across the country and leveraged that to position Bell PBX solutions in all regions.    AT&T then renamed Lucent, have been operating in Canada since the early 80’s selling its line of Definity PBX and Merlin key systems.  In 2000, the company’s Business Communications Division was re-branded Avaya and spun off from Lucent Technologies (which retained the Telco communications division) in order to focus on the Enterprise Communications business (PBX’s).   

As of 2009, over one million businesses worldwide, including more than 90% of Fortune 500 companies use Avaya’s solutions for IP telephony, unified communications and contact centers.