Internal WinModem won’t connect to PPP

Client with Boca WindStorm 56k voice modem (internal Tapi device) can’t connect to 56 US Robotics on Unix host for PPP and normal login. User sees “Gibberish” in terminal window and cannot enter user id and password. Looks like a baud rate problem but all settings in Control Panel -> Modems are correct. Also speed settings in Dial-Up networking and Terminal software are correct.Other clients with external modems work fine. US Robotics modem is set to connect at incoming baud rate. Unix port is set at 38400. I feel this is a windows Tapi issue as external modem works correctly. Clues appreciated. More info available by e-mail if needed.