A modem that plugs into an expansion slot within the computer. Unlike an external modem, an internal modem does not provide a series of display lights that inform the user of the changing modem states. The user must rely entirely on the communications program. Contrast with
external modem.
Modem Housings
There are three ways that modems are connected to a computer. The internal modem (left) plugs into an expansion slot. The external modem (middle) plugs into the serial port, and the PC Card modem (right) plugs into a PC Card slot. (Image courtesy of U.S. Robotics.)