Published on Jun 05, 2023
Voice (and fax) service over cable networks is known as cable-based Internet Protocol (IP) telephony. Cable based IP telephony holds the promise of simplified and consolidated communication services provided by a single carrier at a lower cost than consumers currently to pay to separate Internet, television and telephony service providers.
Cable operators have already worked through the technical challenges of providing Internet service and optimizing the existing bandwidth in their cable plants to deliver high speed Internet access. Now, cable operators have turned their efforts to the delivery of integrated Internet and voice service using that same cable spectrum.Cable based IP telephony falls under the broad umbrella of voice over IP (VoIP), meaning that many of the challenges that telecom carriers facing cable operators are the same challenges that telecom carriers face as they work to deliver voice over ATM (VoATM) and frame-relay networks.
However, ATM and frame-relay services are targeted primarily at the enterprise, a decision driven by economics and the need for service providers to recoup their initial investments in a reasonable amount of time. Cable, on the other hand, is targeted primarily at home. Unlike most businesses, the overwhelming majority of homes in the United States is passed by cable, reducing the required up-front infrastructure investment significantly.Cable is not without competition in the consumer market, for digital subscriber line (xDSL) has emerged as the leading alternative to broadband cable. However, cable operators are well positioned to capitalize on the convergence trend if they are able to overcome the remaining technical hurdles and deliver telephony service that is comparable to the public switched telephone system.
In the case of cable TV, each television signal is given a 6-megahertz (MHz, millions of cycles per second) channel on the cable. The coaxial cable used to carry cable television can carry hundreds of megahertz of signals -- all the channels we could want to watch and more.
