A measurement of how fast data is moved from one place to another. A 56K modem can move about 57,000 bits per second.

Computer modems for twisted pair telephone lines usually operate at 57.6 Kbps or, with Digital Subscriber Line (DSL) service, at 512 Kbps or faster. So-called "cable modems," designed for use with TV cable networks, can operate at more than 1.5 Mbps. Fiber optic modems can send and receive data at many Mbps.