What is a winmodem?

Winmodem is a generic term for a modem that uses software in place of hardware for certain functions. In technical terms, winmodems lack an instruction processing chip called a controller; winmodems are also referred to as controllerless modems or host-based modems. Winmodems that also lack a UART (Universal Asynchronous Receiver Transmitter) are referred to as HSP (Host Signal Processor) modems.

The term "Winmodem" is a registered trademark of 3 Com/U.S. Robotics. It was first applied to the U.S. Robotics Sportster line of 33.6Kbps controllerless modems and was later the name for the controllerless 56K Sportster modems as well. But while Winmodem is a registered trademark, most people have accepted the word winmodem as covering both controllerless and HSP modems made by any manufacturer for the Windows platform.

Because winmodems lack a controller and sometimes a UART, they depend on the computer's CPU for these functions. With 486 and Pentium computers, this was a significant amount of processing power taken away from applications. New computer CPUs are powerful enough that this is no longer a problem.

To determine whether the modem you are planning to purchase is compatible with your version of Windows, check the hardware compatibility list at: