The ADSL.Lite bandwagon took on some key players last week
from outside of North America, adding both support and complexity to the drive to make
high-speed telco data a mass-market reality.
Five overseas telcos said they had joined the Universal
Asymmetrical Digital Subscriber Line Working Group (UAWG), greatly expanding the market
potential for vendors that will supply gear built to the proposed standard. The five are:
British Telecom, Deutsche Telecom (Germany), France Telecom, National Telephone &
Telegraph (Japan) and Singapore Telecom.
Overseas ADSL Group
At the same time, the new members added new points of
self-interest to the standard drafting process, which already shows signs of being delayed
until at least a few weeks beyond the targeted completion date.
The UAWG has moved swiftly toward completion of the first
draft of ADSL.Lite, its proposed consumer plug-and-play version of ADSL, said Jeff
Waldhuter, executive director of technology and engineering at Bell Atlantic Corp. The
group has based its version of ADSL on the American National Standards Institute's T1.413
protocol. Major U.S. local-exchange and long-distance carriers,
telecommunications-equipment vendors and computer companies are members of the UAWG.
But Waldhuter acknowledged that unresolved issues could
push completion of the draft beyond the initially targeted mid-June deadline.
While Waldhuter and other UAWG representatives don't think
that the delay will extend beyond a few weeks, they made it clear that they don't expect
to see mass deployment of ADSL.Lite modems until well into next year.
"I think that you'll see prototype equipment available
for lab tests and field trials by the end of the year, but it will take a while beyond
that point to get the volume quantities that we need for commercial launches,"
Bell Atlantic, which is running four ADSL trials, plans to
move to limited commercial deployments during the third quarter, using an alternative
technology at first, and migrating later to both T1.413 and ADSL.Lite, said Bell Atlantic
spokesman Larry Plumb.
The telco will target the service toward the "high-end
consumer market" and corporate telecommuters, he said, declining to be specific about
locations or other details of the planned rollouts.
So far, members of the UAWG have agreed on an adaptive-rate
approach to ADSL.Lite that will support a top downstream rate of 1.5 megabits per second,
backing off in increments of 32 kilobits per second to accommodate specific wiring
conditions, Waldhuter said.
By closely following the architecture laid out by version 2
of T1.413, which vendors are already implementing in hardware, the UAWG will be able to
expedite both the standards-proposal process and the move to vendor implementation once a
draft specification is completed, he added.
But there are differences on key issues that must still be
resolved, including the question of what segment of spectrum must be reserved to combat
line noise, which is crucial to making "splitterless" DSL possible.
There will be some homes where the wiring is too poor to
accommodate plugging an ADSL modem into standard jacks without the use of special filters
on existing lines or the installation of a second in-home line. But carriers aren't
certain what the trade-off between bandwidth for payload and bandwidth to combat noise
should be, given differences in individual markets and an overall lack of knowledge about
home-wiring conditions in general.
"We and a number of other regional companies are
studying in-home wiring configurations now, and we will combine those data to get a better
idea of what it looks like out there," Waldhuter said.
"As a service provider, I'm concerned about maximizing
the number of households that this technology can reach, especially since once you get
much over 384 kbps, the bottleneck shifts from the access side to the back end of the
Internet, including Web sites that aren't set up to accommodate high-speed access,"
The expansion of the UAWG membership adds to the market
power of the initiative, but it also brings complications to the specifications-setting
For example, where U.S. carriers generally say that their
facilities could support a market reach of 60 percent to 70 percent with the
implementation of T1.413-compliant modems, France Telecom is looking at much higher
penetration levels based on its line conditions -- probably in the 80 percent range, or
better -- said Sabrice Andre, a technical advisor in the company's
This means that France Telecom's noise-tolerance threshold
for achieving even higher penetration levels with splitterless ADSL is much higher than
those of U.S. carriers, Andre noted.
"The ability to achieve mass scale requires that the
customer be able to install the modem, which is why we support the UAWG effort,"
Andre said. But, he added, it remains to be seen whether ADSL.Lite is the right horse to
ride. "We haven't made any decisions yet on mass deployment," he said.
Generally speaking, U.S. and Canadian carriers have been
more aggressive about deploying ADSL than carriers elsewhere, which means that the new
members add new perspectives on timing and on the trade-offs between waiting for improved
technology and being first to market.
France Telecom -- which, like the other new members of the
UAWG, has ADSL tests under way, but no commercial deployments -- sees Internet access as
the immediate market-driver, but it is also preparing to expand testing of non-Lite
versions for possible use in delivery of video services, as well as data, Andre said.
The good news for the telephone industry is that whenever
UAWG members reach agreement on a specification, it won't take long for vendors to produce
modems. The UAWG would then pass its specification on to the International
Telecommunications Union as the recommended approach to what the ITU calls
Not only does the conformance of ADSL.Lite to T1.413
expedite the process, but the fact that the architecture is based on
digital-signal-processor technology is a major benefit, as well, Waldhuter said.
"Most implementations of the standard use DSPs, which
can be programmed in firmware to conform to the new specifications without requiring new
fabrication," he said.
A new generation of DSPs coming into the market later this
year also offers major improvements with respect to power consumption and processing
speed, Waldhuter said.
Telcos also anticipate that they'll get a boost in the
marketplace from vendor delivery of new, 56-kbps analog modems that are equipped with DSPs
that can support ADSL.Lite once it becomes available.
Lucent Technologies, a member of the UAWG, said it would be
able to supply modem vendors with a chip set supporting both data systems in time for
retail distribution at year's end.
The availability of such chip sets will make it easier for
modem vendors to begin supplying DSL-capable modems in advance of telco line-provisioning
for DSL rollouts. This should help to alleviate the chicken-and-egg problem surrounding
retail distribution of ADSL.Lite modems, said Bob Rango, general manager of market
development with Lucent's Microelectronics Group.
"In the real world, a modem has to be able to
communicate at whatever rates are available from the service provider," he said.
Meanwhile, expansion of the market base for ADSL in advance
of UAWG-compliant systems continued last week. U S West Communications said it had
launched its "MegaBit" service in the Twin Cities of Minnesota, following
launches in Phoenix, Denver and Boise, Idaho. And in New York, DualStar Technologies
Corp., a start-up group, said it was preparing to launch ADSL to apartment-dwellers later
this year, using facilities supplied by Teleport Communications Group.