Comtech EF Data CDM-600/600L - Manual (Page 174)

CDM-600/600L Open Network Satellite Modem Revision 3
Open Network Operations MN/CDM600L.IOM
12–2
12.2 IBS
Primary Data Rates Supported
G.703 1544, 2048, 6321, 8448 kbps SD, RD
RS-422, V.35, LVDS N x 64 kbps SD, RD (up to 8448 kbps)
ADPCM Audio (2 Channels) 64 kbps only, full duplex
Engineering Service Channel
Earth Station-to-Earth Station
Channel RS-232 data synchronous at 1/480 of the primary data
RS-232 data asynchronous at 1/2000 of the primary data
High Rate Engineering Service Channel
ESC Data Interface Type
Async – configurable async character format, RS-232 (up to 1/20 th of
the primary data rate)
ESC Data Rate Example: 2400 baud at 64 kbps
Faults and Alarms
Satellite Backward Alarm 1 (per IESS-309)
Receive BWA Output Enabled onto terrestrial secondary alarm
12.2.1 IBS Clock/data recovery and De-jitter
Performs clock and data recovery on the G.703 format. Clock de-jitter and data encoding/decoding
is done as with the IDR configuration.
12.2.2 IBS Framing
Multiplexes/demultiplexes the primary data in compliance with the standard IESS-309 overhead
ratio of 1/15 (4 overhead bytes per 60 data bytes) and provides the rate exchanged transmit clock to
the modulator portion of the base modem.
12.2.3 IBS Engineering Service Channel
Bi-directional processing of the components of the ESC channel, including the ASYNC or SYNC
RS-232 data channel, and fault/alarm indications.
A second high-rate ESC channel, at up to 1/20th of the primary data rate is available, using ASYNC
RS-232 format.
12.2.4 IBS Scrambling
Provides the synchronous scrambling/descrambling of the satellite-framed data specified in IESS-309.
Base modem scrambling/descrambling is disabled in this mode.