D-Link DI-106 Series User Manual page 49

9. Enter the S/T bus number if the router is connected to an ISDN
PABX. If this field is left as blank then the loopback test will be
skipped.
When you are finished, press ENTER at the message 'Press
ENTER to Confirm...' to save your selections, or press ESC to
cancel. When you press ENTER, the router will use the information
that you entered to initialize the ISDN link to the telephone
company switch. It should be noted that whenever the switch type
is changed, the ISDN initialization will take slightly longer. In
addition, if you are using the U-interface, the system will also take
slightly longer to initialize.
At this point, you will be asked if you wish to check if your ISDN
line has been successfully connected to your router. If you select
Yes, the router will perform a loop-back test to check the ISDN
line. If the loop-back test fails, note the error message that you
receive and take the appropriate troubleshooting action.
Installation 41