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CDM-625 Advanced Satellite Modem
Front Panel Operation
Receive
Unit
Network
BUC
LNB
Demod Lock: indicates either the demodulator or the following FEC decoder cannot
lock to the incoming signal.
AGC Alarm: is indicated if the demod signal level is out of range.
Frame Sync: indicates that the de-framing unit (EDMAC, IBS or IDR) or Reed-
Solomon outer decoder cannot synchronize to the data being sent to it by the demod
and/or FEC decoder.
Buffer Slip: occurs when Doppler or Plesiochronous effects cause the Rx data buffer
to empty or fill completely, which results in a reset to 50%.
Rx AIS: Alarm Indication Signal (all 1's) present at the Rx satellite input is monitored.
EbNo Alarm: occurs when the monitored level drops below that programmed by the
user via menus: Config, Rx, EbNo Alarm point.
Buffer Clock: indicates that the desired buffer reference is not present, causing the
buffer to fall back on Rx satellite timing to clock its output.
Loss TxFrm: Loss of Tx frame occurs in Drop & Insert operation, when the incoming
T1 or E1 frame cannot be found by the modem.
BER >10E-3: This error rate monitor is enabled for IBS and IDR framing.
Loss TxMul: Loss of Tx multiframe occurs in E1-CAS D&I operation, when the
multiframe marker for CAS signaling data cannot be found.
Tx Sig AIS: An AIS condition in the signaling positions of an incoming E1-CAS frame
is monitored.
Tx Terr RM indicates the presence of the Tx terrestrial remote alarm on the incoming
T1 or E1 frame.
IBS Rx Rem indicates the presence of the IBS satellite remote alarm (backward
alarm) on the incoming IBS frame from the transmit side of the link.
IDR Rx BW1-4: Multi-destinational backward alarms are the corresponding satellite
alarms used by the IDR frame structure.
IDR Tx BW1-4: Backward alarms 1-4 indicate that the hardware inputs available on
the back panel of the modem have triggered, resulting in the corresponding Tx
backward alarm being generated by the modem's IDR framer.
BUC current
BUC voltage
BUC checksum or bad comms
BUC PLL
BUC temperature
LNB current
LNB voltage
5–49
MN-0000036 (Ref MN/CDM625.IOM)
Revision 1
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