ADTRAN L128 - Manual (Page 125)

Chapter 4: Troubleshooting
108 Express L128/L128T User Manual 61202.070L1-1
probably something wrong with the translation of the line. The phone ser-
vice provider should be able to help.
3. If the PWR LED still flashes, there is a physical problem with the phone
line (more than likely, a problem with the Layer 1 setup). The problem is
in one or more of the places listed below:
• The Express L128/L128T software setup
• The Express L128/L128T hardware
• The wiring on your premises
• The telephone service provider’s wiring
• The telephone service provider’s hardware
• The telephone service provider’s software setup
To isolate the problem, perform the following procedure:
A. Ensure the line is plugged into the Express L128/L128T
connector marked ISDN on the back of the Express L128/
L128T.
B. Make sure the Express L128/L128T is configured for Dial
line service.
C. If possible, try another piece of functioning ISDN equip-
ment with a U-interface on the line.
D. Talk to your service provider and ensure you have an
ISDN Basic Rate U-Interface with 2B1Q line coding.
(Wrong options are an S or T interface or AMI line cod-
ing).
E. Ensure that your phone line is connected to the actual
telephone line (U-interface) provided by your telephone
company. Make sure your line is not connected through
another piece of equipment such as an NT1 in a wiring
closet.
F. Make sure nothing else is bridged across the line pair.
G. With a minimum of extra wiring, try connecting to the
line pair at the point where the service provider’s wiring
ends.