cellular modem

A device that adds wireless 3G or 4G (LTE) connectivity to a laptop or desktop computer. Typically available as an external USB module, the modem may also be on a PCI or PCI Express (PCIe) card that plugs into an empty slot on the motherboard. For older laptops, modems may be available for ExpressCard or PC Card/CardBus slots.

Known By Many Names
A cellular modem via USB is a "USB modem." On a card, it can be an "air card," "data card" or "broadband card." Generic terms are "broadband adapter," "broadband modem," "cellular adapter," "3G or 4G modem."

Alternatives: Smartphones and Routers
While the cellular modem plugs directly into the computer, smartphones and stand-alone broadband routers convert cellular signals into a Wi-Fi hotspot for nearby devices. See cellular hotspot and mobile broadband router.

An Internet "Stick"

Connecting via USB, this Verizon modem adds 3G CDMA cellular data service to a computer or tablet. (Image courtesy of Verizon Wireless.)

A Hotspot and Tethering

This Android Galaxy Note 3 smartphone provides cellular data service by becoming a hotspot or by cabling directly to a computer via USB (see tethering). Older cellphones were occasionally used as dial-up modems for a computer.