SCTE 133 2017 (R2021)

Downstream RF Interface for Cable Modem Termination Systems

This document defines the downstream radio-frequency interface [DRFI] specifications for:

  • an edgeQAM (EQAM) modular device, or
  • an integrated Cable Modem Termination System [CMTS] with multiple downstream channels per RF port, or
  • an integrated CMTS beyond DOCSIS 2.0.

There are differences in the cable spectrum planning practices adopted for different networks in the world. Therefore two options for physical layer technology are included, which have equal priority and are not required to be interoperable. One technology option is based on the downstream multi-program television distribution that is deployed in North America using 6 MHz channeling. The other technology option is based on the corresponding European multi-program television distribution. Both options have the same status, notwithstanding that the document structure does not reflect this equal priority. The first of these options is defined in Sections 5, 6, 7, whereas the second is defined by replacing the content of those sections with the content of Annex A. Correspondingly, [ITU-T J.83-B] and [CEA-542-B] apply only to the first option, and [EN 300 429] only to the second. Compliance with this document requires compliance with the one or the other of these implementations, not with both. It is not required that equipment built to one option shall interoperate with equipment built to the other.