American Telephone & Telegraph Co. and a partner have announced that they plan to develop a device that would sit on a home television set, much like a cable converter box, but decipher movies and other video services over telephone lines rather than the thick coaxial cable of the cable-television operator.
AT&T; and the partner, Compression Labs Inc., have not developed a prototype or determined a possible price range for the device but said it would be aimed at both consumers and businesses.
Moreover, in order for the device to work, the hundreds of central offices of the local phone company would have to be rewired with new hardware and software to raise the carrying capacity of telephone lines nearly 80 times.
The AT&T; device is one of what will be a growing number of new technologies unleashed by the government’s decision last year to allow telephone companies to carry video services. The Federal Communications Commission decision pitted phone companies, which have lines into virtually every American home, directly against cable companies, which have lines to about 60 percent of households.
Under the agreement, AT&T; Paradyne, a concern based in Largo, Fla., that helps develop data-communication products for the parent company, will cooperate with Compression Labs, an outside vendor in San Jose, Calif., that helped AT&T; develop its consumer video phone.
Compression Labs specializes in compression algorithms that edit the prodigious amounts of information in a television signal down to the trickle that can be carried on a household telephone line.
On a home television set, the equivalent of more than 45 million bits of information are displayed. A cable-TV coaxial cable can easily carry that amount, but a telephone line can only carry substantially less than 1 percent, or 19,200 bits.
Compression Labs’ algorithm only edits the television signal down to 1.5 million bits. Telephone companies must still install new equipment that sharply increases the capacity of telephone lines.
