A wireless adapter that connects a laptop computer to a cellular telephone system for data transfer. Cellular modems, which contain their own antennas, plug into a PC Card slot or into the USB port of the computer and are available for a variety of wireless data services such as GPRS, EDGE and EV-DO.

Cellular Modems Vs. Cellphone Modems
If a cellphone has a built-in modem, it can function like a wireless counterpart to a landline modem. Early cellphones offered an analog modem option for dial-up service, while later smartphones added high-speed, digital data services. Such phones plug into the USB or serial port of the computer or transmit via Bluetooth, the latter providing a wireless connection from computer to cellphone.