The problem with finding OEM USR drivers is that in order to use the current driver you must update the firmware. This file will update your USR 56K Voice winmodem to current code. Then the OEM drivers from usr will work.
The following files are found inside the driver download file.
|turbovbf.vx_||3.9 KB||4 Oct 1996|
|Mdminfo.ini||693 bytes||3 Jun 1998|
|Winmodem.inf||59.8 KB||15 May 1998|
|Cleanwm.exe||229.9 KB||6 May 1998|
|Wmldr.vx_||3.5 KB||1 Apr 1998|
|Wmexe.ex_||25.3 KB||1 Apr 1998|
|Deleteme.exe||22.0 KB||20 Mar 1998|
|wmwave.inf||1.1 KB||1 Apr 1998|
|turbovcd.vx_||9.4 KB||4 Oct 1996|
|Wmaudio.vx_||3.4 KB||1 Apr 1998|
|Winmodem.vx_||343.0 KB||1 Apr 1998|
|Wmdll.dl_||21.8 KB||1 Apr 1998|