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D3CM1604V EMTA Cable Modem Administrator Manual
Appendix A - Glossary
Term
Definition
Correctables
Number of codewords that were detected to be damaged, but could be repaired by the EMTA.
Downstream
The direction from the head-end toward the subscriber. The downstream channel carries data from
the ISP's head end (UBR) to your EMTA.
DS1
Digital Signal 1. A T-carrier signaling method that is widely used standard in telecommunications in
North America and Japan to transmit voice and data between devices.
EMTA
Embedded Multimedia Terminal Adapter. A device that combines a DOCSIS cable modem and
analog telephone adapter. The cable modem provides the data interface and the telephone
adapter provides the voice over IP (VOIP) interface for one or more telephones. The terminal
adapter provides the conversion between analog voice signals and IP packets, delivers dial tone,
and manages the call setup.
Payload Header Suppression
A feature of DOCSIS 1.1 and 2.0 in which header bytes that are common in a sequence of packets
of a Service Flow are replaced by a 1-byte PHSI Index (PHSI) when transmitting the packet on the
RF network.
Uncorrectables
Number of codewords that were detected to be damaged beyond possibility of repair by the EMTA.
If this count is increasing, the downstream signal conditions are unacceptable, regardless of how
good the SNR and power figures look on the Connection page (see “Viewing Network Connectivity”
on page 38). Uncorrectables disappear after a reboot because the EMTA resets its counters to
zero without store that data permanently in its memory.
Upstream
The direction from the subscriber toward the head-end. The upstream channel carries data from
your EMTA to the ISP's head-end.