Latched Alarms; Backward Alarms; Ibs Fault Conditions And Actions - Radyne DMD20 Installation And Operation Manual

DMD20/20LBST Universal Satellite Modem
6.2.2.2

Latched Alarms

Latched Alarms are used to catch intermittent failures. If a fault occurs, the fault indication will be
latched even if the alarm goes away. After the modem is configured and running, it is
recommended that the Latched Alarms be cleared as a final step.
6.2.2.3

Backward Alarms

Backward Alarms are alarms that are fed back to or received from the other end of the satellite
link. In IBS Mode (including Drop & Insert), Backward Alarm 1 is the only one used. It would be
received if the distant end demod drops lock.
6.3

IBS Fault Conditions and Actions

Figure 6-1 and Table 6-1 illustrate the IBS Fault Conditions and Actions to be taken at the Earth
Station, at the Terrestrial Data Stream, and the Satellite. These faults include those detected on
the Terrestrial link and those detected from the satellite.
MN-DMD20-20LBST Revision 14
Figure 6-1 IB S Alarm Concept
Maintenance and Troubleshooting
6–7