For fax functions of the ISDN card, you need to install software to have the function. Such as the optional bundled software RVS-COM lite.

If your RVS-COM is V1.12 or later, you can use the RVS printer driver to send the G3 fax. It will be much easier than to use the Microsoft Fax.

If you are using the Microsoft Fax for sending G3 faxes, please check the property of the Microsoft Fax (Control Panel/ Mail and Fax/ Microsoft Fax/ Properties) to see if the ‘MODEM’ is selected to be ‘RVS Fax ISDN FAX G3'.