The Gateway SoftK56 Data Fax driver is specifically for the Gateway SoftK56 PCI modem, which is a type of soft modem (software modem) that uses a combination of hardware and software to function. The "SoftK56" refers to the K56flex technology, which was a modem standard for dial-up connections that allowed for speeds of up to 56 Kbps, commonly used for faxing, data transfer, and dial-up internet access before broadband technologies became widespread.
The Gateway SoftK56 Data Fax driver enables Windows to communicate with the modem, allowing it to be used for faxing or dialing out for internet connections. Without the driver, the modem won't function correctly.