Excerpts from 8/30 Dow Jones story on Ariel's Dave Sobin's contribution to ADSL.
Other modem-makers products may hit the market first, but 'they're not currently selling all the added features that Dave Sobin has been able to perfect over at AT&T, '' when he designed CO-LAN systems for local phone companies, said GKN Securities Corp. analyst Anthony Stoss. CO-LAN stands for Central Office Local Area Network.
ADSL, which Sobin says evolved from CO-LAN, is so attractive to phone companies now because it gives them a way to offer high-speed Internet access and other services, such as video, without building out new, expensive transmission networks. Phone companies are, however, exploring the long-term option of constructing new fiber optic networks.
The CO-LAN systems made by Sobin's team at AT&T ''never really caught on, Sobin said, since the Internet wasn't popular when the technology was developed in the mld-198Os. Phone companies who bought the Systems from AT&T sold them mainly to large corporations, universities and hospitals, whose employees used the technology to link up with their office computer networks from home.
But those systems worked essentially the same way that ADSL does now according to Sobin. High-tech computer chips installed in two ADSL modems-one in a user's home and the other in a phone company's central office-transform telephone line so it can carry data or video signals at extremely h~gh speeds. Signals move back and forth over the cable at two different rates, butt can flow from a central office to a home as quickly as 1.5 megabit per second That's at least 50 times faster than today's conventional, analog modems.
But according to Sobin,speed isn't ADSL's biggest selling point. The more important advantage is that it allows users to talk and use computer modems connected to the same telephone lilne. The technology, like the old CO-LAN, conveniently divides the pnone line to create separate pathways for data and voice traffic.
Although CO-LAN systems are now defunct, industry players are confident their conveniences will return if phone companies deploy ADSL on a widespread, consumer basis. |
