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 modem" and "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.