Idr Primary Data Interfaces; Idr Engineering Service Channel - Comtech EF Data CDM-625 Installation And Operation Manual

CDM-625 Advanced Satellite Modem
Open Network Operations
14.4.1

IDR Primary Data Interfaces

When configured for IDR operation, the board performs these functions:
• Receives and performs clock and data recovery on incoming G.703 T1 and E1
pseudo-ternary data.
• Clock dejitter is performed per G.823 and G.824, and any data decoding (AMI,
B8Z5, or HDB3) required per G.703 is also accomplished.
• IDR Framing
Multiplexes in compliance with the standard IESS-308 96 kbps ESC overhead onto the data and
provides both the data and rate exchanged clock to the modulator portion of the base modem.
Performs the corresponding demultiplexing of Rx satellite data received from the demodulator
portion of the modem. Resulting G.703 data is optionally encoded (AMI, B8ZS, or HDB3) before
being output.
14.4.2

IDR Engineering Service Channel

Bidirectional processing of the components of the ESC channel, including the ADPCM audio
channels, 8 kbps data channel, and fault indications specified by IESS-403 and IESS-308.
Option of using the ADPCM portion of the satellite overhead for a single 64 kbps ESC data
channel in addition to (and with the same format as) the 8 kbps data channel.
When using G.703 format for the primary IDR data path, the P3B primary data interface (25-pin)
is used for the 8kbps overhead channel. If EIA-422 or V.35 is used, P3B becomes the primary
interface and the 8kbps channel is unavailable.
MN-0000036 (Ref MN/CDM625.IOM)
14–6
Revision 1