History GTE ad 1972 interconnect [telecom]

Historically, General Telephone/Automatic Electric sold their equipment to (1) independent telephone companies and (2) to businesses seeking a private internal system that was not connected to the outside Bell network.

But in 1972 GTE/AE was advertising their systems to business in direct competition to Bell, as shown by the following ad in a business magazine:

Also, in that issue Bell advertised its 800A PBX