Text on Display Description / Cause / Notes Relays To Terr To Sat Other
P300H P300 Series Installation and Operating Handbook Page 221
RX TRAFFIC FAULTS (Bottom line of disp’l Rx Traffic Faults: Rx OK LED Off and Rx Traffic (prompt) relay.
Rx Fault: Demod unlocked at <nn.nnnn>MHz The Demod cannot find a carrier to lock to at the specified frequency. Check the frequency, check T TA,TC SB RF
the Data rate and FEC settings (use Info, View Config, Rx). Perhaps check the demod itself by
enabling a IF Loopback (Test, Loopback, IF).
Rx Fault: FEC sync lost (demod locked) The Demod can lock to the carrier, but the inner FEC decoder (Turbo, Vit or Seq) cannot lock to the T TA,TC SB RF
demodulated data. Check you have the correct FEC settings (ie Turbo, Vit or Seq as appro p riate,
use Info, View Config, Rx). The most common other cause is Spectrum Inversion, you can check
this by temporarily turning on the Rx Spectrum Inversion (Change, Rx, Demod Spect Inv).
Rx Fault: De-interleaver sync lost The Demod can lock to the carrier, and the inner FEC decoder to the demodulated data. However the T TA,TC SB RF
Reed-Solomon De-interleaver cannot find sync with the decoded data. Check the RS de-inter leaving
depth, then the values of `n` and `k`(use Info, View Config, Rx). On Non-Paradise Tx modems,
check the V.35 scrambler is not enabled in addition to the Reed-Solomon scrambler.
Rx Fault: Fr ame sync los t The modem cannot find the IBS or ID R frame s ync on the recei ve data. Check the Rx Service T TA,T C SB RF
settings (Change, Rx, Service), although as the service type affects the composite data rate over
satellite, it is more likely the demod will fail to lock rather than this message appear if the wrong
service type is selected. On Non-Paradise Tx modems, for IBS, check the V.35 scrambler is not
enabled in addition to th e IBS/SMS scrambler.
Rx Fault: TS32 Multiframe sync lost The modem cannot find the IBS TS32 Multiframe sync on the receive data although it has found T T A,TC SB RF
Frame sync ( otherwise t he message above wou ld display) . This i s only likely in Custom IB S modes
where the operator has the option of sending a TS32 Multiframe or not. Note th at for low data rates
the standard IBS/SMS multiframe period can be long (1 sec at 32kbps) and it may be best to use
Custom IBS without a TS32 MF for rates of below 32kbps to improve the acquisition time if the
carrier is momentarily lost.