Future of DSL technologies is bright, advocates say
- By William Jackson
- Apr 12, 1999
Digital subscriber lines are poised to take over the last mile of existing local
telephone networksat least according to DSL proponents.
There is more than light at the end of the tunnel, said John Freeman, an
analyst at Current Analysis Inc. of Sterling Va. It seems like we are emerging from
At the end of last year, symmetric and asymmetric DSL technologies together had an
installed base of only about 39,000 users in the United States. But the next two years
will likely see rapid growth, said Laurie Falconer, a DSL analyst at TeleChoice Inc. of
I think 1999 is the year for business, Falconer said. 2000 will be
the year for residential.
William V. Rodey, marketing vice president at Westell Technologies Inc. of Aurora,
Ill., and vice chairman of the ADSL Forum, said government use of the technology will
parallel commercial adoption. DSL already is going in at some military bases that have
copper wire infrastructures, he said. In his opinion, telecommuting will be the driving
application for government use.
Like DSL, telecommuting has yet to take off among federal workers.
Its almost to the threshold of catching on, said Wendell Joice, a
research psychiatrist in the General Services Administrations Telework program.
GSA plans to promote telecommuting for federal workers in the Washington area because
of highway construction that will tie up interstate traffic for several years in Northern
Virginia, Joice said. He said GSA is interested in testing ADSL for the telecommuters.
The assessments of current and future prospects at last months quarterly meeting
of the ADSL Forum in Washington were not exactly objective, because the groups
mission is to build a mass market for ADSL. The technology transmits high-bandwidth data
over existing copper telephone lines while keeping another channel available for
simultaneous voice calls.
Speakers painted a picture of a maturing technology operating in a regulatory
environment thatdepending on ones point of vieweither encourages or
discourages competition and investment.
Using compression to take advantage of the digital capacity of existing unshielded
twisted-pair wiring, symmetric DSL can send up to 2 Mbps both upstream and downstream as
far as 12,000 feet from a telephone companys central office.
ADSL can deliver up to 8 Mbps downstream and 640 Kbps upstream over distances of 18,000
feet from a central office. A special DSL modem is required at both the user end and the
central office. The modem has a filter that splits off a channel for voice calls.
More than 34 million customers are served by central offices already equipped with DSL
Of the 39,000 customers now using DSL, more than 80 percent have incumbent local
exchange carriers. The rest have competitive LECs.
Freeman said several drawbacks must be overcome for widespread use of DSL: high cost,
lack of modem interoperability and interference among different technologies using the
LECs local loop bundles.
The chip set vendors are too busy reducing die size and power consumption to
invest resources in interoperability, Freeman said. The poor condition of much of
the existing public switched telephone network infrastructure will demand large
investments before DSL becomes generally available. Even so, it is having an impact.
Fort Bragg, N.C., plans to buy up to 1,000 ADSL gateways for remote users it cannot
economically link to the bases asynchronous transfer mode fiber backbone. Some of
the forts phone wiring is more than 50 years old, but ADSL works fine on it anyhow,
So far, less than 2 percent of the federal work force has tried telecommuting. The
biggest hurdle now is managerial resistance, GSAs Joice said
Its a culture change for them, he said. But as government downsizing
bottoms out and environmental factors become a growing concern, telecommuting might become
a common benefit for government employees.
If managerial resistance lessens, DSL could be an answer to technical problems that
William Jackson is a Maryland-based freelance writer.