U10C034 MSO User’s Manual v1.4 June 2008
ix
CMTS
Cable Modem Termination System. A device at a cable headend that
connects to cable modems over an HFC network to an IP network.
CPE
Customer Premises Equipment. Subscriber-owned equipment con-
nected to the network. Technically, a cable modem, MTA, or eMTA
falls into this category, although many operators do not designate them
as such.
CODEC
COder-DECoder. In VoIP products, one of several possible schemes of
converting audio (i.e. a phone call) to digital data and vice versa.
Attributes of a CODEC include fidelity (e.g. voice quality), bandwidth,
and latency.
DOCSIS
Data Over Cable Service Interface Specification. The interoperability
standards used for data communications equipment on an HFC
network.
DTMF
Dual Tone Multi-Frequency. The tones generated by touching the keys
on the phone are used for a variety of purposes including voice mail
systems and voice messaging. Also known as Touchtone.
eMTA
Embedded MTA. A device, such as the AMBIT U10C034 Telephony
Modem, that contains both an MTA and a Cable Modem.
Euro-DOCSIS
The European version of DOCSIS. Euro-DOCSIS specifies an 8 MHz
downstream bandwidth (vs. 6 MHz for DOCSIS); other minor
differences exist as well.
G.711
G.711 is an ITU-T standard for audio companding. It is primarily used
in telephony. This audio standard is mandatory for all video
conferencing systems. It requires a data rate of 56 or 64 kbit/s and
provides an audio bandwidth of 300 ... 3400 Hz.
G.729
G.729 is an audio data compression algorithm for voice that
compresses voice audio in chunks of 10 milliseconds. Music or tones
such as DTMF or fax tones cannot be transported reliably with this
codec, and thus use G.711 or out-of-band methods to transport these
signals. Also very common is G.729a which is compatible with G.729,
but requires less computation. This lower complexity is not free since
speech quality is marginally worsened.
HFC
Hybrid Fiber-Coaxial. A broadband, bi-directional shared media
transmission system using fiber trunks between the headend and fiber
nodes, and coaxial distribution cable between the fiber nodes and
subscriber premises.
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