Section 363-742-102
Revision 01
Page 11
TABLE 3. FRL-742 RT LINE UNIT TROUBLESHOOTING
Indication
Problem
Action
POWER LED
off
1. One or both HDSL lines
are no longer connected
between the COT and RT.
Verify the connections at
the RT and COT.
a. Make the following measurement on the RT Enclosure backplane:
•
130 Vdc to 250 Vdc between HDSL_T and HDSL_T
b. Make the following measurements on the COT Shelf backplane:
•
-130 Vdc, ±10%, between HDSL_T1 and Chassis Ground
•
0 Vdc to +120 Vdc, between HDSL_T2 and Chassis Ground
2. The COT Line Unit fuse
F1 has blown.
Replace the fuse.
3. The RT Line Unit power
supply has failed.
Replace the RT Line Unit.
4. The COT HDSL power
supply has failed.
Replace the COT Line Unit.
LOOP 1 (2)
SYNC LED
flashing or off
1. The HDSL line is
attempting to synchronize
with the central office unit
or cannot detect the
HDSL signal from the
central office unit. This is
usually an indication that
there is a problem with
the HDSL circuit between
the COT and RT
(assuming the FAULT
LED is off).
2. COLU and RTLU
incompatible i.e. one is a
T1 version and the other is
an E1.
a. Verify the HDSL circuits are terminated properly and with the
correct orientation.
b. Measure the loop resistance of each HDSL circuit (shorting the pair
at the far end). The loop resistance must be less than that shown in
Table 1.
LOOP 1 (2)
MARGIN LED
on
The HDSL line margin level
is below a preset level.
See the previous discussion on the SYNC LED flashing or off.
FAULT LED on
Faulty FRL-742 RT Line
Unit.
Replace the RT Line Unit.
