We are planning to use CDR data on CUCM for billing purposes. During our initial testing, we have identified the Call Duration shown on CDR is slightly innacurate: as soon as the FXO port connects, the call is considered to be running and the timer starts counting, even if we only here the ringing tone.
As a result, we are getting calls with 15-20 sec duration where there was no call established, hence these are calls we shouldn´t count for billing.
The question would be: is there any parameter either on CDR/CUCM or the Gateway, that can help to correct this timing innacuracy? How do you guys overcome this timing difference when you set up a billing system?
Comments are welcome!