Diagnostic tool to monitor ports on Portserver II

We are using banks of modems which rout call data to our Sun/software via a Digi Portserver II.
We are trying to run some diagnostics to track dropped calls. On the modem/call switch side we have a call counting software which counts all calls routed to the modems, and on our software side we log all call/data.
Somewhere in between many calls are being dropped.
Is there some diagnostics tool for the Portserver II to help track or monitor the number of calls that go through to the ports?
We are looking at the port authority software, but it doesn’t seem to be very helpful.