Trunk Utilisation logging?

We have two trunks connected to our FreePBX system, one is ISDN/PRI, the other is SIP.

We have a range of incoming numbers, some attached to the ISDN and some attached to the SIP trunks.

On a few occasions recently we’ve had people complaining about engaged tones when calling in on various numbers and its become apparent that we currently have no way of monitoring how busy each trunk is.

Clearly each trunk has a limited number of active calls and we would like to have a method of logging the number of active channels over the day, so we can see how often we are reaching saturation point where all channels are busy.

Anyone got any ideas how this could be achieved?

Cheers

The 3rd party module, Call Statistics is capable of reporting maximum concurrent calls between user specified periods on the system or on specific trunks: