Comtech EF Data SDM-9000 - Manual (Page 147)

SDM-9000 Satellite Modem Theory of Operation
Rev.4 5–19
5.5.2 Digital Interface Specifications
Main Channel
Physical Interfaces G.703
ECL/PECL
MIL-STD-188
Scrambling/Descrambling IDR, per IESS-308
V.35, per CCITT V.35
EFD (SDM-450 compatible)
None
Buffer (Optional) Plesiochronous
Buffer Size 2 to 32 ms, in 2 ms steps
Buffer Clock Source TX Terrestrial
RX Satellite (Bypass)
External
Internal
Buffer Centering Manual and automatic on buffer underflows/overflows
Buffer Depth Displayed on front panel from 1 to 99%
Internal Clock Stability ± 100 PPM
Loopback Baseband
Interface
Reported Faults and Alarms TX Data/AIS
TX Clock PLL
TX Clock Activity
TX Programming
TX Configuration
Buffer Underflow/Overflow
Buffer Full
Buffer Clock PLL
Buffer Clock Activity
RX Data/AIS
Frame BER
DEMUX Lock
RX 2047 Lock
RX Programming
RX Configuration
Engineering Service Channel
ESC Audio AS/3971 2 duplex ADPCM channels
ESC Audio AS/5618 2 duplex ADPCM channels, or one 64 kbit/s RS-422
data channel
Audio Encoding CCITT G.721
Audio Interface 600 Ω transformer balanced 4-wire.
Audio Input Level -20 to +10 dBm for 0 dBm, in 1 dB steps
Audio Output Level -20 to +10 dBm for 0 dBm, in 1 dB steps
Audio Filtering Internal 300 to 3400 Hz input/output
ESC Data Channel 8 kbit/s, RS-422
Data Phasing Per RS-449: data changes on the rising clock transition
and is sampled on the falling edge
Octet Timing Octet high with every 8th bit: aligns with frame bit d8