The Hayes PCI Modem Enumerator is a Windows device driver that allows the operating system to communicate with a Hayes-compatible modem connected through a PCI (Peripheral Component Interconnect) slot in your computer. Modems are used for dial-up internet connections, faxing, or other types of data communication over telephone lines. The "Enumerator" in the name suggests that this driver is responsible for detecting the modem on your system and enabling it to work with the Windows operating system.