Solution:

The driver disk that ships w/ PCM-3600 has a variety of different modems from 2 different manufacturers. How do I identify the correct driver? Windows 95 OSR2 automatically selects a DataSytems 3314 PX/MX(1)/XB, but the modem does not operate correctly w/ this driver. Versions of Win95 less than OSR2 fail to identify any modem at all. Please use driver dtxmodem.inf and select "Discovery 3314 HP Internal Card" as modem model. After reload, Windows 95 will detect and add another modem. Just don't care this modem or delete it, use "Discovery 3314 HP Internal Card" for you application.