In telecommunications, data rate units are commonly multiples of bits per second (bit/s) and bytes per second (B/s). For example, the data rates of modern residential high-speed Internet connections are commonly expressed in megabits per second (Mbit/s).They are used as units of measurement for expressing data transfer rate, the average number of bits (bit rate), characters or symbols (symbol rate), or data blocks per unit time passing through a communication link in a data-transmission system.