RoadRunner
U S E R S G U I D E
4
The
RoadRunner
can be equipped with any of the Digital Interface
Modules available from MUSICAM USA. Available modules include
internal Terminal Adapters (with or without built-in NT-1), V.35, X.21,
RS530 or RS422.
Front panel indicators include Power, On line, Norm (signal level) and
Clip (over level). There are also four Cue LEDs indicating the state of
the internal relays. The front panel keypad can be used to access all
functions of the
RoadRunner
and built in Terminal Adapter, and is also
used as the dial keypad. A backlit display with adjustable contrast
provides menu, maintenance and dialing displays.
Since
RoadRunner
features and audio quality are implemented in
software, rather than hardware, the
RoadRunner
can be upgraded in
the field should improvements become available. Software can be
downloaded directly from our Web Site (
www.musicamusa.com
) or we
can send you an upgrade kit. This prevents your
RoadRunner
from
becoming obsolete.
CODEC Compression Algorithms
There are currently three coding algorithms used in the
RoadRunner
.
Each has its advantages and disadvantages. Which algorithm you use
depends on a number of factors, including desired audio quality, delay
and compatibility with other codecs.
ISO/MPEG Layer III
ISO/MPEG Layer III can provide full duplex, 15 kHz monaural audio
using only one 56 or 64 kb/s ISDN ‘B’ channel. When using 112 or 128
kb/s, transparent 20 kHz monaural audio is possible. The inherent
drawbacks of this algorithm are the long coding delay times and poor
cascading characteristics. In addition, post processing may highlight
some artifacts.
MUSICAM and ISO/MPEG Layer II
The premier coding algorithm used in
RoadRunner
is MUSICAM,
MUSICAM USA’s encoding enhancement to the ISO MPEG Layer II
algorithm. MUSICAM encoding is fully compatible with all MPEG
Layer II decoders, and since the enhancements area part of the encoder,
any Layer II decoder will sound better when connected to a