ADTRAN Express XLT - Manual (Page 124)

Chapter 4: Troubleshooting
108 Express XL/XLT User Manual 61200070L1-1
2. Disconnect the Express XL/XLT. From a functioning voice phone, call the
local directory number(s) provided with your line. Calling a good ISDN
line with nothing connected usually results in a ring or fast busy tone. If
someone answers, or you get a not-in-service intercept, there is probably
something wrong with the translation of the line. The phone service pro-
vider should be able to help.
3. If the Loop LED still remains off, then there is a physical problem with the
phone line (more than likely, a problem with the Layer 1 setup). The prob-
lem is in one or more of the places listed below:
• The Express XL/XLT software setup
• The Express XL/XLT 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 XL/XLT con-
nector marked ISDN BRI U on the back of the Express
XL/XLT.
B. Make sure the Express XL/XLT 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.