Carrierless Amplitude/Phase Modulation
<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)