Taipei, Taiwan -- The push to make coax the medium of choice for audio/video and data networks in the home is quietly gathering steam as top-tier chip makers signal their support for the Mul- timedia over Coax Alliance (MoCA).

Last week, leading set-top box chip makers Conexant Systems Inc. and STMicroelectronics said they would develop MoCA-compliant chips. Another recent addition is Broadcom Corp. In total, there are now seven chip suppliers in the consortium--a far cry from last fall, when startup Entropic Communications Inc. was the sole chip provider.

The additions are a nice boost for MoCA, which had aggressively touted its suitability as a home-networking solution and gathered a bevy of supporters like Comcast, Cox Communications, EchoStar Technologies and Verizon. So far, however, only Verizon has deployed the technology, using set-top boxes from Motorola.

In North America, operators seem to favor coax as the backbone for home multimedia, said Kurt Scherf, principal analyst at Parks Associates. Coaxial will be especially important in the United States, where 70 percent of households say they have coax jacks in the living room and 83 percent have them in master bedrooms, according to a Parks Associates study.

Yet, privately, operators had been expressing concern about Entropic as the single source. "The one rub I've heard about the MoCA solution is its higher chip set price, so the move to embrace it as a networking solution by these major vendors is a boost in terms of higher volumes and lower prices," analyst Scherf said.

Ladd Wardani, president of MoCA, said, "Operators need to see that it is going to get into the SoCs [systems-on-chip] of Broadcom and ST and Conexant because, when it's standalone, it's $10. But when it's integrated, it's $5 and dropping rapidly."

Entropic estimates that it will ship 1 million chip sets by early June. Around that same time, it will come out with a lower-cost, smaller version of its flagship c.Link-270 chip design, which offers physical-layer (PHY) rates of 270 Mbits/second with packet prioritization and full Data Encryption Standard encryption. Because the architecture allows pass-through of tree-and-branch splitters, the chip set can be used both for in-home broadband networking and broadband access.

Entropic notched another key design win with J-COM earlier this year in Japan.

In the United States, Wardani estimates that MoCA-based technology will be deployed in 1 million homes by the third quarter--still not that many, but a huge gain over the thousands of homes it was in at the same time last year. In total, Parks Associates estimates that perhaps 400,000 North American homes had whole-house digital video recorder solutions by the end of last year. That number will grow to 1.7 million by the end of 2006, predicted the firm, with MoCA representing the lion's share.

Cable operators have a natural attraction to MoCA, which has a real-world throughput of more than 100 Mbits/s--enough overhead for a few high-definition video streams, trick modes such as pause and fast-forward, and additional audio or data services. Yet, Verizon's deployment shows its appeal extends beyond the cable community.

MoCA's recent momentum doesn't mean it has eliminated the competition. Powerline networking is gaining momentum, with large companies like Intel Corp. renewing support for the technology and small companies like Spain's Design of Systems on Silicon S.A. winning deployments in Europe.

So, coax-based networking isn't a panacea, said Jeff Crosby, vice president of Conexant's Broadband Media Processing group. There are still limitations on where coax can go.

The challenge that remains for chip makers at this early stage of distributing video over home networks is that operators aren't satisfied with one approach. Some want MoCA, some want powerline and some still want phone line or Ethernet-based video distribution. "None of them want to pay the overhead to have other solutions in the chip sets," said Crosby. n