Fujitsu FLM 150 ADM Maintenance And Trouble Clearing page 49

Maintenance and Trouble Clearing
FJTU-320-515-480
Table 3-3: AIS (Alarm Indication Signal)—Alarm Event (cont'd)
AID
Direction
Type
OVTG
TRMT
150 ADM
OC-3/
OC-12
ADDED
SIGNAL
STS1
RCV
150 ADM
OC-3/
OC-12
DROPPED
SIGNAL
T1 NA
TRMT
(LC1A-D1 or
LC1A-D1E
unit installed)
TRMT/RCV
(LC1A-D1 or
LC1A-D1E
unit installed)
TRMT
(Transmux
unit installed)
T2 TRMT
T3 TRMT/RCV
VT1 RCV
Issue 9, May 1999
Probable Cause
The locally received optical virtual
tributary group (OVTG) signal
contains an AIS. This indicates a
remote failure.
The STS signal demultiplexed from
the OC-3 contains an AIS. This AIS
can result from an upstream failure
along the STS path. Possible
failures include OC-3 failures (such
as an LOS) and T3 input failures
(such as a T3 LOS).
A failure on the input side of the
building integrated timing supply
(BITS) timing source.
A DS1 far-end NE (such as a
channel bank) has lost its
downstream input and has inserted
an AIS.
TRMT: The DS2 input contains an
AIS.
TRMT: The DS3 input contains an
AIS.
RCV: An upstream failure.
The virtual tributary (VT) signal
demultiplexed from the OC-3
contains an AIS.
FNC and FNC Customer Use Only
Suggested Corrective Action
Retrieve the alarms at the remote FLM 6
site.
• Check for an upstream OC-3/OC-12
signal failure.
• Check for a service-affecting alarm
where the tributary signal enters the
far end of the ring.
• Verify that the HC1A or MC1A unit is
in service and has not failed.
• Check for deleted STS-1 cross-
connects.
• Refer to the timing source vendor
documentation for procedures to
isolate and repair the failure.
• Retrieve the alarms from the upstream
sites.
Check for alarms on the upstream
asynchronous equipment.
Check for alarms on the upstream
asynchronous equipment.
• Check for OC-3/OC-12 signal failure.
• Verify that the HC1A or MC1A unit is
in service and has not failed.
• Check for a deleted VT cross-connect.
Vol. ll, Page 480.3-7
3.5: AIS