Not much reaction on that subject introduced recently. It IS a hot topic in several professional publications recently. URLs at the end! Digital Subscriber Line technology is the latest and greatest in possible offerings for high speed telecommunications. It resulted from the *failed* video-on- demand trials of a couple of years ago. Basically, it provides a mechanism to off-load digital traffic from the voice switches onto the digital trunk (the same one used by ISDN) and back onto the analog lines at the switch nearest the destination. There are four main varieties of xDSL with ADSL as the most discussed and likely. Costs are a bit prohibitive at this time; but just think of what would happen if the telcos started buying it in volume and brought about economies of scale.
The speeds it now allows are 1.5 to 6 Mbps downstream and 64kbps to 1.5Mbps upstream using POTS (Plain Old Telephone Service.) The future portends speeds of 26 to 52 Mbps downstream and 2 to 8 Mbps upstream as the service providers upgrade to OC3 and then to OC48 (2.4Gbps) trunks and install the higher speed switches to utilize these trunks. The main differences between the different varieties are speeds, distances of viability, transmission medium and potential areas of use. All eight major US phone companies have trials going on; a couple of them are given freely to customers with regular phone service. Trials are also going on in Europe and Australia.
The technology is dependent on
DMT technology patented by Stanford University and Amati Communications Corp.
and licensed to Motorola, NEC, Texas Instruments and Northern Telecom. The list
of licensees shows that there is a level of confidence among the major players
in manufacturing from telecom switches to end user electronics. For more
information see the following: Electronic Engineering Times at:
Jan 20,'97 Telecommunications: http://www.telecoms-mag.com/tcs.html
several issues
Peace,
Clarke
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