4 intermediate data rate (idr) – Comtech EF Data CDM-625 User Manual
Page 375

CDM-625 Advanced Satellite Modem
Revision 15
Open Network Operations
MN-CDM625
14–5
14.4 Intermediate Data Rate (IDR)
Primary Data Rates Supported
G.703
EIA-422 (Replaces 8K Overhead)
V.35 (Replaces 8K Overhead)
1544 kbps SD, RD
2048 kbps SD, RD
6312 kbps SD, RD
8448 kbps SD, RD
Engineering Service Channel
ESC Audio
2 duplex ADPCM channels
Audio Encoding
CCITT G.721
Audio Interface Type
600Ω transformer-balanced 4-wire
Audio Input Level
Nominal Input : 0dBm0 (-3dBm, 600Ω)
Adjustment range: -6 to +8 dB, 2 dB steps
Audio Output Level
Adjustment range: -6 to +8 dB, 2 dB steps
Audio Filtering
Internal 300 to 3400 Hz input and output
ESC Data Interface Type
EIA-422
ESC Data Rate
8 kbps, also 64 kbps if ADPCM audio is not used
ESC Data Circuits Supported
SD, ST, RD, RT, Octet in, Octet out
Data Signal Phasing
Per EIA-449, data changes on the rising clock transition, is
sampled on the falling clock edge
Octet Timing
Octet high with every 8
th
bit, aligns with frame bit d8
Faults and Alarms
Backward Alarms Supported
4 input, 4 output
Backward Alarm Inputs
1 kΩ pull up to ground, set high to activate.
Backward Alarm Outputs
Form C Relay, N/O, N/C, Com