DMD20/20LBST Universal Satellite Modem
Maintenance and Troubleshooting
MN-DMD20-20LBST Revision 14
6–4
6.2.1.4
Minor Rx Alarms
Alarm
Possible Cause
BUFF UNDERFLOW
Indicates that a Doppler Buffer underflow has occurred.
BUFF NEAR EMPTY
Indicates that the Doppler Buffer is about to underflow.
BUFF NEAR FULL
Indicates that the Doppler Buffer is about to overflow.
BUFF OVERFLOW
Indicates that a Doppler Buffer overflow has occurred.
RX DATA ACTIVITY
Indicates that there is no Rx Data activity. For the Ethernet
Interface, indicates that no Ethernet port is active (no cable
is plugged in).
SAT AIS
Indicates that AIS has been detected in the receive satellite
data stream.
DnI FRAME LOCK
Indicates if drop/insert data is frame locked.
DnI M-FRAME LOCK
Indicates if drop/insert data has multiframe lock.
INSERT CRC
Indicates if the Circular Redundancy Check is passing in
PCM-30C and PCM-31C Modes.
T1/E1 SIGNALING
Indicates that the T1/E1 Signal is not locked.
IFEC LOCK
Indicates that the Inner Codec is not locked.
OFEC LOCK
Indicates that the Reed-Solomon Decoder is not locked.
INTERLEAVER
Indicates that the Reed Solomon Interleaver is not
synchronized.
EBNO (dB)
Indicates that the Eb/No is outside of limits.
IBS BER
Indicates that there are more than one in 1000 bits in error
in IBS mode.
RX DVB FRAME LOCK
Indicates that the Rx Satellite Data Stream Framing is not
DVB.
LNB CURRENT
Indicates that current is either below or above the threshold
limits of the BUC, as specified by the modem. Only active
when voltage is enabled.
LNB VOLTAGE
Indicates that voltage is not functioning correctly when
voltage is enabled.