< communications > (CAP) A design of Asymmetric Digital Subscriber Line transceiver developed by Bell Labs . CAP was the first ADSL design to be commercially deployed and, as of August 1996, was installed on more lines than any other.
CAP is a variation of Quadrature Amplitude Modulation , the modulation used by most existing modems in 1997. With CAP, the three channels ( POTS , downstream data and upstream data) are supported by splitting the frequency spectrum. Voice occupies the standard 0-4 Khz frequency band, followed by the upstream channel and the high-speed downstream channel.
(1997-10-08)