OL3.FEB–rp
Modem achieves world's fastest speed over standard phone lines
A modem that transmits data at a rate of 28,800 bits/s over standard
telephone lines has been developed by Largo, FL-based AT&T Paradyne.
According to the company, the modem achieves the world's fastest such
transmission speeds and helps prepare the way for the forthcoming CCITT V.
fast communications standard, which is expected to be approved either late
this year or in early 1994. Currently, the fastest standard modem speed
is 14.4 kbits/s, as specified by the CCITT V.32bis standard. The V.fast
specification, which was originally to have covered speeds of first 19.2
and then 24 kbits/s, is intended to address the 28.8-kbit/s transmission
rate. When used with error correction and data compression, modems
operating at this speed will be capable of providing a throughput rate of
up to 115.2 kbits/s. AT&T says it is the first company to have provided
actual 28.8-kbit/s test results to the CCITT V.fast standards committee.
The only other 28.8-kbit/s test results were achieved by companies using
simulated modem modulations, rather than with actual modems. AT&T's modem
is based on a chipset currently used in the company's Comsphere 3800
products, and uses a new modulation scheme to achieve its speed. A
modulus conversion enables the device to transmit data at nonlinear
nonintegrated numbers of bits per symbol. According to Richard McCartney,
Product Marketing Manager for AT&T Paradyne, the modem appears to operate
reliably even over relatively poor phone lines. Prior to the approval of V.
fast, the company intends to make the modem available to customers who
need the high speed and are not concerned with what would still be a
proprietary modulation scheme. Users of the company's Comsphere 3800
products will be able to upgrade their existing modems to the V.fast
standard when it becomes a reality. For more information, contact AT&T
Paradyne at 800-484-3333 or . –Richard Pell Jr.
PULLOUT:
Modems operating at this speed will be capable of providing a throughput
rate of up to 115.2 kbits/s.
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