P300H
P300 Series Modem Installation and Operating Handbook
Page 224
signal on any G.703 cards in use (see note 3).
Tx Fault: Clock loop fail, Tx muted
The Tx clock generation loop, which generates the timing over the satellite link has failed and the Tx
carrier is muted as a result. If the Tx Clocking (Change, Tx, Clocking) is set to Tx Clock In , then
check
the Tx Clock frequency matches the data rate (Change, Tx, Baseband, Continuous).
Tx Fault: BUC DC current outside limits
The Modem is configured to operate with a BUC and the operator has activated the BUC current
monitor, but the current drawn by the BUC is outside the low/high window set. View the current
drawn and alarm settings with
Monitor, BUC
, change with
Change, BUC/LNB, Tx/BUC, Current
Monitor
Tx Fault: BUC current/connection fault
The Modem is configured to operate with a BUC and the modems DC supply to the BUC has been
activated, but the DC switch indicates either an open or short circuit.
TX WARNINGS
(Top line of display)
Tx Traffic warnings: Deferred alarm relay only
Tx Warn: Reconfiguring Tx path
The modem is reconfiguring the Tx path (after a user parameter change).
Tx Warn: Data marginal, clock inv ?
The phase of the input Clock and Data is checked to ensure the data is stable when it is actually
latched into the modem. This message means that the data is changing at this critical time, and it
WILL CAUSE DATA ERRORS.
Check
the A & B clock lines are not reversed. (Data A & B should be
stable on the rising edge of Clock B, the falling edge of Clock A)
Tx Warn: Line code violations det
G.703 interfaces have several different line codes. For 1544kbps they are typically AMI and B8ZS,
and for 2048kbps they are AMI and HDB3. Normally the LATTER is the one, which is used. The
interface must be configured to match the line code of the other equipment; otherwise line code
violations (ie terrestrial data errors) will occur. See Note 3
Tx Warn: Transmit FIFO slip
The FIFO, which interfaces the Drop Mux to the Framer has slipped (full or empty). This should never
occur in operation (contact factory).
Tx Warn: Backward alarm at Tx input
A Frame Backward Alarm is detected at the Tx Input. This indicates that equipment downstream of
the RECEIVE path has failed and is returning an alarm. This may be due to
any
receive downstream
equipment, but
could
be due to the modem Rx output failing.
Check
the modem Rx path indicates
OK,
Check
the Rx data output from the modem is connected to the downstream equipment.
Tx Warn: TS16 MF Back' alarm at Tx input
A Multiframe Backward Alarm is detected at the Tx Input, this indicates that equipment downstream
of the RECEIVE path has failed to find multiframe sync and is returning an alarm. The Modem only
detects this alarm when the Tx baseband is set to use the Drop mux in a G.732 mode and CAS
signalling has been selected (or 2048k IBS G.732 0% overhead mode with CAS is enabled). On the
Rx path, if the Insert Mux bearer is set to Generate, then
check
the Rx path is also utilising CAS,
otherwise it will generate a bearer without a TS16 Multiframe.
Tx Warn: Tx input BER > User threshold
The Bit Error Rate at the Tx input (measured on the PCM Frame Alignment Words) is worse than the
user set threshold for a deferred alarm (Change, User-Opt, Thresholds, User BER). This warning will
be replaced with a Fault message at 1x10
-3
.
Check
the line code setting (AMI/B8ZS/HDB3) matches
the input signal on any G.703 cards in use. See note 3
Tx Warn: Framer slipping data to sync
After a break in the Tx input data, the framer is `bit slipping` data in the Transmit FIFO to bring the
data taken out of the FIFO by the framer into step with the satellite frame timing. It bit slips (rather
than force the frame timing into step with the data) to prevent causing a frame sync loss in the distant
end equipment.
Tx Warn: Framer slipping sig' to sync
See above text, but this time with regard to CAS signalling data not the main data path.
Tx Warn: Framer Sig' FIFO slip
The FIFO, which carries the CAS signalling from the Drop Mux to the Framer, has slipped (full or