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PERCEPTIONea,,
Tl/OS-1
SEPTEMBER 1991
channel(s)
via dip switches
on S3. Hardware
faults (such as a bad channel)
can cause this
to light.
2) BSY-Busy
indication
in one or more chan-
nels.
3) FALM-NDTU
has not achieved
Synchroni-
zation (see Note 1).
4) MFALM-NDTU
has not achieved
Frame
Synchronization
(see Note 1).
5) YALM-Yellow
alarm is detected
by NDTU.
6) BALM-Blue
alarm is detected
by NDTU.
NOTES:
1. Combination
of FALM and MFALM is red
alarm.
2. If any alarms
are /it, refer to the Trou-
bleshooting
flowcharts.
YALM
MFALM
0
0
0
0
0
0
1
FALT
BSY
BALM
FALM
FIGURE II-LED POSITIONS
3.60
Alarm
and Status
Conditions
3.61 The NDTU
PCB is equipped
with six LEDs.
These LEDs are the indicators
for different
alarms
and status
conditions,
that are generated
either
locally or remotely.
The following
are the commonly
defined
alarm and status conditions
in the Ti/DS-1
interface.
These alarms, LED indications,
and LED
definitions
are also noted in Chapter
4, Paragraph
7.00
in
the
Installation
section
of
the
'
PERCEPTlONe&ex
installation
and Maintenance
manual.
1) Red Alarm:
The red alarm is generated
when
a Loss of Signal (LOS) or Out of Frame (OOF)
condition
has occurred for a period of 2.0 w 3.0
seconds.
This alarm is identified
as a locally-
detected
error, and it is a combination
of the
FALM and MFALM
alarms.
2) Yellow Alarm:
The yellow alarm can be iden-
tified as a remotely-detected
alarm, as follows:
l
Superframe:
When the second bit of each
channel orthe eighth bit is forced to"ZER0."
YALM
MFALM
I
FALT
BSY
BALM
FALM
FIGURE g--RED ALARM
YALM
MFALM
0
FALT
0
BSY
-:@- 0
BALM
0
0
FALM
FIGURE g-YELLOW ALARM
-8-
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