No Windows 98 specific drivers were ever written...the modem is too old for those. The Windows 95 drivers should work ok in Windows 98.
Davicom V1433VQH-U P/N 89931310, Windows 95 drivers
The following files are found inside the driver download file.
|dos/SETCOM.EXE||47.3 KB||2 May 1997|
|ASKEY.INF||22.3 KB||15 Jul 1997|