I've had surprisingly good luck with the HiRo USB modem (Agere/LSI Soft Modem) on my PSTN analog line connected to a Panasonic PBX. IVM 5.11 works fine with everything I've tried (running Windows 7 with that most recent version of the modem s/w, ver 18.104.22.168), EXCEPT for one critical failure.
When the caller presses a key (say, '2'), IVM is supposed to flash, dial ext. 215, wait for an answer, and then hang up on answer or fail back to the call tree if no answer. I monitor the progress of an incoming call. The modem recognizes the incoming DTMF tones without fail. It correctly applies the flash hook. I hear the stutter, then dial tone, and then ... nothing. IVM activity log claims it is dialing 215, but it doesn't. Here's the activity log fragment:
22:19:33 Command - Transfer
22:19:33 Dialing: !
22:19:35 Dialing complete
22:19:41 Dialing: 105
22:19:41 Dialing complete
22:19:46 Call disconnected
When I use a phone and manually flash, then dial 215, it works fine. It's just the IVM is not sending the keys. Period. And the modem logs show that no DTMF signals are being issued by IVM; it just disconnects.
By the way, IVM version 4.11 unders Windows XP has worked flawlessly for me for many years.
Any suggestions from NCH wizards on why IVM is behaving badly?