Always difficult to predict the future of a particular technology. ISDN doesn't get much respect from the leading edge crowd for a variety of reasons, but line growth is close to 100% a year and accelerating. ADSL is interesting but as of yet embryonic. Lots and lots of technical issues, let alone cultural for the telcos, tariffs, etc.
My crystal ball says: ISDN in the 1990s and something else next decade. That something else wil more likely be something called VSDL, hooked up to SONET and ATM-based Digital Loop Carrier systems. This is the way the telcos will implement a concept known as "fiber to the neighborhood."
In plainer English: fiber goes all the way to neighborhoods, copper the last mile or so (today, copper is a lot more than a mile). Within a half-mile to a mile, VDSL (Very-high=bit-rate Digital Subscriber Line) will run at up to 50 mbps. When it's ready, VDSL and ADSL will be instinguishable because both will be "rate adaptive," i.e. will sense distance and tranmission obstacles and adjust speeds accordingly.
All of this will take a couple of decades. In the meantime, look for ISDN as a mass market service (will get much cheaper in next couple of years) and HDSL as higher-priced, higher-speed LAN extension to the home. That's my take on it, but as Dennis Miller says, "I could be wrong." |
