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 ...

Enter the isolated USB null-modem. The device consists of two USB Communication Device Class, or CDC chips, creating a USB serial port for each attached computer. The TX and RX lines are cross ...