This driver is for use with Compaq Presario Laptop model 1625 and others that use the same modem. The original Compaq driver which is reconized as Compaq Presario 56K DF is hard to find and the 336DF56K drivers will not work with it. This driver is actually from Lucent Technologies, but works great with the 56K DF modem. I believe they are both the same as Windows reconizes these drivers for that modem with no problems, but the device manager will now show it as Lucent Win Modem instead of Compaq Presario 56K DF. Install is simple, just run the executable which is a self-extracting WinZip file which will in turn run the setup.exe automatically after decompression.