At the CM, this object describes the PHY characteristics of a downstream channel. At the CMTS, it describes the PHY signal quality of an upstream channel. An entry in this table exists for each ifEntry with an ifType of docsCableDownstream(128) for Cable Modems. For DOCSIS 1.1 Cable Modem Termination Systems, an entry exists for each ifEntry with an ifType of docsCableUpstream (129). For DOCSIS 2.0 Cable Modem Termination Systems, an entry exists for each ifEntry with an ifType of docsCableUpstreamChannel (205).