The Bell System ran several ads in Billboard magazine touting its contribution to broadcasting. Billboard covered the entertainment industry.
On 8/12/1957, pg 15, Bell noted it's high speed broadband switching facilities that allowed advanced setup.
On 3/9/1957, pg 16, Bell noted its automatic protection switching that instantly switched a bad TV channel to a backup so fast that the changed wasn't noticed.
Also, back on 3/11/1944, an article describes the future plans of Bell and others to implement television transmission facilities to allow coast-to-coast broadcasting.
On all of these, you can scroll through the entire magazine. Interesting business history.