AT&T Paradyne's Bandwidth Revolution

Phone lines that carry 6312 Kbps. That's the promise of AT&T Paradyne's new GlobeSpan transceiver chip set. GlobeSpan uses a technology called asymmetric digital subscriber line (ADSL) over ordinary phone lines, eliminating the bother of rewiring the entire planet with fiber-optic cables. The one-way data speeds would be up to four times as fast as a T-1 line and about 400 times faster than a 14.4 modem. Return bit rates would be about 64 Kbps (hence the "asymmetric").

Besides a leased GlobeSpan modem, of course, your telephone company would also have to incorporate the technology at its end. Telephone companies reportedly are eager to do this, and some have suggested that Globe Span service could be available as early as this summer.

GlobeSpan is built on ADSL and the related technology, high-bit-rate digital subscriber line (HDSL). ADSL uses one unshielded copper wire pair, up to 18,000 feet. HDSL, in turn, is based on the 2B+D flavor of Basic Rate ISDN and uses two full-duplex pairs of unshielded copper wires, up to 12,000 feet. Doubler units can boost this distance two or three times.

A related technology, symmetric digital subscriber line (SDSL), may be even more attractive to some users, says Garrick Case, a spokesperson for AT&T Paradyne. SDSL allows two-way bandwidth on the order of fractional T-1. This would allow, for example, live videoconferencing at home. AT&T Paradyne will support ADSL, HDSL, and SDSL within the same chip set.

With this kind of bandwidth, on-line providers are thinking of producing their own programming. If the modem and service are inexpensive enough, the Internet will become far more attractive as a medium for aud io and video broadcasting.