Despite this, some proponents for the other main modulation scheme for VDSL, quadrature amplitude modulation (QAM), also came here with improved versions of their devices. The latter group includes Infineon Technologies, Cisco and Metalink.

The 11 companies now pushing seamless migration to VDSL broadband access include the dominant players in shipping ADSL ports. They include Alcatel, Analog Devices, Inc., Ikanos Communications, Texas Instruments, ST Microelectronics, Broadcom Corporation, Ericsson, Intel Corporation, LSI Logic, Thomson Multimedia and Nokia.

The companies are also taking their lead from most standards bodies, which are pushing towards DMT as the VDSL line code. A final decision is due within the next few months. Only the European Telecommunications Standards Institute still favors two versions of VDSL modulation schemes.

Broadcom had previously promoted QAM, but earlier this year switched camps, suggesting DMT offered the clearer and more cost effective upgrade path from ADSL to VDSL.

"After pioneering QAM VDSL chipset development for many years, Broadcom now supports DMT as the right choice for the VDSL line code," said Dan Marotta, Vice-President and general manager of Broadcom's Broadband Communications Business Unit. "Since we have expertise in both QAM and DMT technology we could have gone either way, but based on our analysis of the latest advancements, we chose DMT as the winning technology."

Matt Davis, director of broadband access technologies for the Yankee Group, said "with 11 of the leading DSL silicon and systems providers supporting DMT, which represents the majority of the DSL market, it is clear that DMT is on track to become the favored modulation for standardized VDSL deployments worldwide.

"Alcatel has supported DMT ADSL from the very beginning," said Willem Verbiest, vice president of its Access Business Unit. Alcatel is the leading DSL supplier with 37.7 percent of the global market. "The best option to move this installed base forward with new DSL technologies, including VDSL, is to build on that same DMT technology base. DMT technology provides optimal performance in the field, while facilitating common management of all DSL flavors," he said.

Behrooz Rezvani, founder and CTO at Ikanos Communications and chairman of the VDSL Alliance, added, "Ikanos has shipped over 500,000 DMT VDSL ports to major carriers worldwide to offer over 50Mbit/s services to consumers. In many evaluations, carriers and system vendors selected DMT VDSL due to its superior performance and overall cost benefits."

Infineon Technologies, however, came to Supercomm with a highly integrated modem-on-chip part for customer premises equipment, based on QAM-VDSL technology. The device, dubbed the VDSL5100I, provides an aggregate rate of over 100Mbit/s. Samples of the part will be available in August.

The OMC incorporates the digital transceiver, analog front end (AFE) and Line Driver for a VDSL modem. The VDSL5100i also features Infineon's new adaptive hybrid technology integrated into the AFE. This enables filterless designs, further reducing the number of external components and associated cost, for both line card and CPE devices. The company said the filterless technology increases the sensitivity of the modem's receiving side.

"With millions of QAM VDSL circuits in use today, service providers and equipment manufacturers are now looking for solutions that reduce total system cost and support new waves of deployment to customer premise locations," said Christian Wolff, vice president of Infineon's Wireline Communications Business Group and general manager of the Access Business Unit. "This makes the VDSL5100i, with its extraordinary level of integration, an ideal solution."