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

Page 375

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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