nThe call drop pattern
nIncreased number of call drops in Iridium-Iridium mode
nThe average time interval between call drops reduced from 100 minutes in case of 4 Iridium-4 PSTN system to 60 minutes in case of 8 Iridium � 8 Iridium DAV system.
nVaries with time and weather
nIncreased call drops in presence of strong radio interference
nModem firmware failures
n�random modem lock ups due to bug in firmware.
nNewer firmware upgrades reduced the number of such lock ups
nPrimary modem failure
nNo longer drops all the modems
nJust the one modem is lost
nSystem operates with remaining 7 modems
