From time to time, user dials a 1800, 1800, 1877, Toll free number, user gets dead air. For testing purposes, I dialed the same toll free number and let it seat for about 2 minutes, after this time, I heard a ring tone, or sometimes heard an IVR, than I can get through. I called the same numbers from my cellular phone and an analog line and got through immediately. Wondering what tools, are avaialble and type of diagnostics I should do to trouble shoot this issue. I have opened a ticket with our telco carrier and they appear to be at a lost.
First of all, if you are the end user, you should give the troubleshooting to reputable consulant, or UC certfied Cisco partner. Then normallt the first trace take in "debug isdn q931" with "term mon".