Developments to Watch
LOWERING THE TOLLS ON THE INFO SUPERHIGHWAY
The cost of the proposed Information Superhighway may not be so daunting after all. Micro Linear Corp., a small semiconductor company in San Jose, Calif., has developed a cheap chip that makes it possible to send high-speed Asynchronous Transfer Mode (ATM) signals, the latest format for sending digitized video, audio, or data over the same lines. If existing phone lines can serve as on- and off-ramps to the infoway, there'll be no need to spend $1,500 on optical-fiber links to each home.
Normally, ATM signals are too fast--at 155 megabits per second--for copper to handle. "Noise" stemming from the metal's electrical resistance contaminates the tightly packed signal, which quickly degrades into a meaningless fuzz. But Micro Linear's chip turns copper's resistance to advantage. By measuring how much strength the signal has lost at the receiving end, the chip can calculate how far the signal has traveled. The chip then adjusts a so-called equalization circuit that filters out the fuzz and restores the original signal. The cost? Just $20 per chip.EDITED BY EMILY T. SMITH