Reply #14: It was a combination of things that made change happen

[TexasProgresive]

The IRS amortization schedule for telcom equipment was something like 30 years. So the telcoms were loath to upgrade. When I first started at GTESW we had cordboards for the operators and electromechanical switching for Direct Dial LD. Local switching was done by Stroger step by step electromechanical switches. Bays of this stuff was still being added in central offices in the early 80s. Digital switching finally began to enter into telecommunications with the #1EAX, #1ESS, Stomberg-Carlson DCO, Northern Telcom DMS 100, TOPS, TSPS.

As far as the Carterfone decision in 1968 telcoms were still forcing modem users to use acoustical couplers. I don't know when they allowed any equipment to be electrically connected to their network- they owned it all from the phone, the drop, the cable and the Central Office.

The Carterfone is a device invented by Thomas Carter. It manually connects a two-way mobile radio system to the public switched telephone network (PSTN), making it a direct predecessor to today's autopatch.

The device was acoustically, but not electrically, connected to the public switched telephone network.

Note the word acoustically.


Acoustic coupler in use

Personally I am not in favor of the break up of the Bell System but I do believe it needed a serious upgrade.