In Geneva and Stockholm today, STMicroelectronics and Telia Research demonstrated the first VDSL (Very high bit-rate Digital Subscriber Line) products to come out of their joint development project announced in June.
The companies' claim the Zipper-VDSL technology will deliver a data capacity of up to 60Mbit/s over conventional copper telephone lines. This would represent an almost ten-fold improvement over ADSL (Asymmetric Digital Subscriber Line) technology, and could theoretically offer home consumers a thousand times the capacity enjoyed by the majority of people dialling in to the Internet over 56Kbit/s analogue modem lines.
Although VDSL remains an embryonic technology without global standards, the partnership is keen that its system will be the first step towards "world standardisation" of VDSL. This step would be necessary before such high-bandwidth connections could become a viable option for the consumer.
The total capacity of Zipper-VDSL is split into 2,048 frequency bands that can be allocated individually. The "Zipper" part refers to the ability to "zip" the bands together in clumps so that the line capacity can be used in any possible configuration. Because it is based upon the same DMT (Discrete Multi-Tone) modulation technique as ADSL and ADSL.Lite, Zipper products will be backwards-compatible with and therefore interoperable with these standards, ensuring the possibility of wider-acceptance for VDSL should it become an industry standard. Claes Nycander, president of Telia confirmed: "The flexibility offered by Zipper-VDSL, including backwards compatibility with ADSL technology should create wide acceptance by Internet users."
The current system is based around a 0.25-micron integrated digital IC (integrated circuit). Initially this would be built as a dual-chip system, but work has already begun developing a sub-micron, single-chip model in the hope that a system could be made commercially available early 2001.
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