RealTime IT News

Comcast Getting Ready For VoIP Primetime

Motorola's SURFboard line of modems, enabled to deliver voice over IP (VOIP) traffic, is one of Comcast's choices for next year's cable telephony rollout, officials announced Friday.

The other two, ARRIS and Terayon, complete Comcast's vision for embedded multimedia terminal adapters (eMTAs), a modem that puts VOIP technology and cable modems in one device. VOIP opens the door to set-top telephony, where customers can access a telephone directory, screen calls using caller ID and other services on a TV set.

Comcast plans to roll out circuit-switched telephony to parts of Philadelphia in mid-2003. The cable operator has been testing Motorola's equipment since April in Detroit. Using older technology, 40,000 users in Michigan in Virginia are using VOIP on Comcast's network.

Details remain secret for now. Tim Fitzpatrick, a Comcast spokesperson, said the costs for VOIP service hasn't been completely worked out yet, as well as the exact locations in Philadelphia the service are going to be available.

Cable technology, available for years now, has been plagued with latency and voice quality issues from the beginning and has been used in test trials by all the major cable networks in the U.S. DOCSIS 1.0, the standard used by cable modem manufacturers, however, was never designed for voice traffic on a data network.

DOCSIS 1.1 has come out in recent times, however, and modem makers have been scrambling to get new modems under the standard certified by CableLabs, the organization that signs off on the equipment's adherence to standards.

Cable operators are eager to roll out VOIP to its customer base because it provides a competing service to the more traditional copper-based telephone service provided by the telephone carriers and brings in more revenues to pay for the digital upgrade they paid millions to accomplish.

There's been a host of problems, though. The cable network's broadband architecture is a shared network resource, meaning the more people on the Internet, the more they are sharing bandwidth, driving speeds down in populated areas. Though VOIP's data packet compression technology reduces a packet to around 8 KB, the potential for dropped packets (i.e., hangups) and an "echo" on the line is huge.

The cable companies would love to tell its customers they can replace its VOIP offering with telephone company-based voice, but they would run into many problems. The biggest factor is emergency availability; if the power goes out, you can't use the phone on a PC or TV.

Fitzpatrick said it was "too soon to say" how it would market the service to it customers, but said the company would have a strategy before the launch next year.