(DOCSIS) ITU-approved interface requirements for cable modems involved in high-speed data distribution over a cable television network. DOCSIS compatible equipment uses a 6 MHz carrier band for downstream, using 64 and 256 QAM (ITU Annex B), and QPSK and 16 QAM for upstream, allowing up to 36 and 10 Mb/s, respectively for downstream and upstream channels.

CableLabs FAQ.