Stentor is an association of 9 telephone companies plus Telesat Canada. Formed in 1931 (opened 1932) as the TransCanada Telephone System (TCTS), and known briefly also as Telecom Canada, the purpose of Stentor is to integrate national telephone service. Until recent years the association lacked employees, assets and legal status, its requirements being met by its members. Prior to formation of TCTS, Canada had relied on transmission facilities in the US for most of its cross-Canada requirements.

Membership of Stentor consists of British Columbia Telephone Co, AGT Ltd, Saskatchewan Telecommunications, Manitoba Telephone System, Bell Canada, New Brunswick Telephone Co, The Island Telephone Co, Maritime Telegraph and Telephone Co, Newfoundland Telephone Co and Telesat Canada. Québec Téléphone, which operates in regions of Québec not served by Bell Canada, is an associate member. With the exception of the Manitoba Telephone System, all members have established holding companies, which in turn hold shares in Alouette Telecommunications Inc, the holding company of Telesat Canada. With revenues in 1993 of $13.5 billion, Stentor accounts for 78 percent of all Canadian telecommunications services revenues.

Stentor itself comprises 3 organizations. The first, Stentor Resource Centre Inc, consolidates the telephone companies' research and development to produce new products and services, expedites delivery of products to the marketplace and facilitates uniform agreement to national technological standards for telecommunications. lt is run by a Council consisting of the chief executive officers of 9 telephone companies. Bell Canada controls directly half of the seats on this Council. The second organization comprising Stentor is Stentor Canadian Network Management, which is responsible for the management and monitoring of the telephone companies' interprovincial network; it also administers the revenue sharing plan for North American interconnections. Finally, Stentor Telecom Policy Inc develops strategies and positions on policy issues, thereby providing a unified voice to represent the telephone companies' interest; it is also the main point of contact for government.