Maintenance
SDM-9000 Satellite Modem
6–26
Rev. 4
6.2.2.2.6 Backward Alarms
Fault/Alarm
Possible Problem and Action
BW ALARM RX4
Receive backward alarm #4.
The distant end of the link is sending Backward Alarm #4. This
indicates trouble at the distant end, which may be a result of improper
transmission at the near end of the link. The modem will signal this
event by setting the deferred maintenance alarm (open collector). This
is essentially a monitor function so the modem reports and records the
event, but takes no other action. Refer to Chapter 2 for the backward
alarm theory of operation. If the user does not wish to monitor the
backward alarm faults, the backward alarm inputs must be grounded at
the breakout panel. Refer to the
B141-1 Breakout Panel Installation
and Operation Manual
for breakout panel pinouts.
BW ALARM RX3
Receive backward alarm #3.
Refer to BW alarm RX 4 for details.
BW ALARM RX2
Receive backward alarm #2.
Refer to BW alarm RX 4 for details.
BW ALARM RX1
Receive backward alarm #1.
Refer to BW alarm RX 4 for details.
BW ALARM TX4
Transmit backward alarm #4.
The modem is being instructed to send backward alarm #4 to the
distant end of the link. This is controlled by wiring the backward alarm
inputs of the modem to the Demod fault relay and/or other fault outputs
in the receive system (see IESS-308 for clarification). The simplest
implementation for single destination service is to wire the Demod fault
relay between ground and the four backward alarm inputs (see
Chapter 2 for clarification). This sends all four backward alarms in the
event of any major (prompt) receive fault. This particular alarm is
transmitted, reported, and recorded, but the modem takes no other
action. In most cases, this will be sent due to some receive problem
with the modem, so a real fault will probably be occurring if backward
alarms are being sent. The transmit backward alarms are a symptom
of trouble, not a cause.
BW ALARM TX3
Transmit backward alarm #3.
Refer to BW alarm TX 4 for details.
BW ALARM TX2
Transmit backward alarm #2.
Refer to BW alarm TX 4 for details.
BW ALARM TX1
Transmit backward alarm #1.
Refer to BW alarm TX 4 for details.
Summary of Contents for SDM-9000
Page 2: ......
Page 5: ...8 Mbit s w IDR Figure 1 7 16QAM BER Performance Curves with Reed Solomon Filename T_ERRATA 3...
Page 8: ......
Page 27: ...SDM 9000 Satellite Modem Introduction Rev 4 1 5 Figure 1 3 SDM 9000 Block Diagram...
Page 42: ...Introduction SDM 9000 Satellite Modem 1 20 Rev 4 This page is intentionally left blank...
Page 64: ...Configuration SDM 9000 Satellite Modem 3 6 Rev 4 JP1 Figure 3 4 Interface PCB AS 3971...
Page 65: ...SDM 9000 Satellite Modem Configuration Rev 4 3 7 Figure 3 5 Interface PCB AS 4477...
Page 66: ...Configuration SDM 9000 Satellite Modem 3 8 Rev 4 JP1 JP6 JP7 Figure 3 6 Interface PCB AS 5618...
Page 70: ...Configuration SDM 9000 Satellite Modem 3 12 Rev 4 Figure 3 7 Nyquist Filter Installation...
Page 83: ...SDM 9000 Satellite Modem Operation Rev 4 4 9 This page is intentionally left blank...
Page 87: ...SDM 9000 Satellite Modem Operation Rev 4 4 13 This page is intentionally left blank...
Page 104: ...SDM 9000 Satellite Modem Operation Rev 4 4 31 This page is intentionally left blank...
Page 107: ...Operation SDM 9000 Satellite Modem 4 34 Rev 4 This page is intentionally left blank...
Page 124: ...SDM 9000 Satellite Modem Operation Rev 4 4 51 Figure 4 17 RF Loopback Figure 4 18 IF Loopback...
Page 150: ...Theory of Operation SDM 9000 Satellite Modem 5 22 Rev 4 Figure 5 6 Interface Block Diagram...
Page 158: ...Theory of Operation SDM 9000 Satellite Modem 5 30 Rev 4 This page is intentionally left blank...
Page 186: ...Maintenance SDM 9000 Satellite Modem 6 28 Rev 4 This page is intentionally left blank...
Page 218: ...Options SDM 9000 Satellite Modem A 32 Rev 4 This page is intentionally left blank...
Page 242: ...Remote Control Operation SDM 9000 Satellite Modem B 24 Rev 4 ref SE_ command...
Page 254: ...Glossary SDM 9000 Satellite Modem g 6 Rev 4 This page is intentionally left blank...
Page 256: ...2114 WEST 7TH STREET TEMPE ARIZONA 85281 USA 480 333 2200 PHONE 480 333 2161 FAX...
