C4 XD / 32 Downstream Cable Access Module

The ARRIS C4c and C4c CMTS eXtended Downstream (XD) Cable Access Module (CAM) supports thirty-two DOCSIS or EuroDOCSIS 3.0 downstream channels. These channels are grouped onto four upconverters. With thirty-two DOCSIS Annex B downstream channels, each upconverter supports eight of the channels. With twenty-four EuroDOCSIS Annex A downstream channels, two of the upconverters each support eight of the channels and the other two upconverters each support four of the channels.

The Physical Interface Card (PIC) of the XD CAM is the same as for the 16D CAM and has four F-connectors with each F-connector connected to the output of one of the upconverters. Each downstream channel on the same upconverter/F-connector must have a unique center frequency, but the channels are not required to be contiguous. The downstream channels on a single F-connector can span up to 78MHz (Annex B) or 80MHz (Annex A) of spectrum, allowing an MSO flexibility in choosing DOCSIS downstream frequencies.