...
Follow the instructions outlined in the page How to take a Diva Trace if instructed to do so by your Dialogic Support Engineer.
Diva Diagnostics - How to take a Diva Trace
If you are already familiar with the ISDN protocol you can use the following tools for your own analysis.
Detailed information about the Diva Diagnostic Trace
ISDN Diagnostic Codes
ISDN Location Codes
ISDN MDL Error Codes