Not My TV

"Toss Your TV: How the Internet Will Replace Broadcasting" was an interesting article. However, asynchronous transfer mode (ATM) is a switching, or more of a "statistical mux," technology; it does not increase the inherent information-carrying capacity of a medium. One cannot compare it with T1 or asymmetric digital subscriber line (ADSL) o r symmetric digital subscriber line (SDSL), which are basically transport systems. For example, a T1 line can carry 1.544 Mbps bidirectionally, and ADSL does 6 Mbps downstream and as much as 640 Kbps bidirectionally. The same T1 or ADSL transport system can have an ATM layer embedded in it, but ATM cannot enable a 12-Mbps transmission in a system that is inherently limited to 6 Mbps.

S.K. Das
Bell Labs, Whippany, NJ
skd@harpo.wh.att.com

Thanks for pointing that out. The article did not make it clear that ATM is in fact defined as part of the Broadband ISDN (BISDN) standard. --Edmund X. DeJesus, senior editor