40-400-00001, Rev. A
31
Troubleshooting
PHYSICAL INTERFACE
Problem: U-SYNC LED does not light.
Solution:
The U-SYNC LED is an indicator for the U interface only and will not
light for the S/T interface.
Solution:
Ensure that the device is connected to the U interface and is 2B1Q
encoded.
Solution:
Ensure that the U interface is terminated into the NT side of an NT-1 or
TE.
Solution:
Ensure that the terminating device (TE or NT-1) is receiving power.
Solution:
Ensure that the loop length between the ILS-1000 and the terminating
device is no longer than 1,600 meters.
Problem: TE indicates no S/T synchronization.
Solution:
Ensure that no more than 300 feet of loop is between the S/T interface
and the TE.
Solution:
Ensure that an NT-1 is not installed between the TE and the ILS-1000.
Solution:
Ensure that any TE loopback tests are completed or disabled
Problem: How do I loopback the S/T interface?
Solution:
The S/T interface acts like an NT-1 device; loopbacks are performed
using S and Q subchannel bits per ITU-TRecommendation I.430.
Problem: How do I loopback the U interface?
Solution:
Select Loopback as the B Channel setting. Received B-1 and B-2
channel data is routed to the transmit B-1 and B-2 paths at each port.
TEI ASSIGNMENT
Problem: The TE cannot initialize TEI
Solution:
Ensure that the physical interface is synchronized.
Solution:
Wait until the ILS-1000 self-test (red/green Status LED blink) is com-
plete (solid green Status LED) before connecting TE.
Solution:
If fixed TEIs (values between1-63) are used, ensure that a different
value is used for each TE at both ports (Note: a TEI value of 0 is not
supported).
