The FCC has accepted an AT&T proposal to conduct a pair of trials in which the company would transition small portions of its network entirely away from traditional TDM-based circuit-switched telephony, to be replaced entirely by an IP network.

The two locations are Carbon Hill, Ala., and West Delray Beach, Fla. Carbon Hill is a rural, sparsely populated area, while West Delray Beach is a large suburban population of older consumers.

The trials are expected to extend for years. AT&T wants to investigate a number of potential issues, including what might be the proper mix of wireline and wireless services to offer (the company will not be ripping out its copper, as reported elsewhere).

AT&T also wants the transition to be voluntary for customers. Those customers who wish to keep circuit-switched service will be able to do so – at least for now.

Ultimately, the company said, circuit-switched telephony is dying. Nearly 70 of the customers in its service area already are either served by VoIP (AT&T’s own VoIP or competitors’ VoIP) or wireless, it noted in its proposal.

AT&T pointed out that its suppliers are beginning to phase out TDM equipment lines. “[I]t is becoming increasingly difficult to obtain needed spare parts to keep legacy TDM networks going. Indeed, as strange as it may seem, AT&T has had to turn to Ebay to locate spare parts for its TDM network,” according to the proposal.

The trials will be in two phases. The first will examine the effects of a cut over to IP. A complete transition of the entire network from TDM to IP will be the second phase, which the FCC will not approve until it is satisfied the transition will not create serious problems.

AT&T also said that it intends to use the trial markets as test markets for “new products and processes that can be used to seamlessly complete the rollout of AT&T's Internet-based network nationally.” The company didn’t get any more specific than that.

The FCC in January gave explicit blessing to such trials, which AT&T and other phone companies have been talking about for more than a year.