A connection point through which information is transferred one digital bit at a time. The rate may be high, e.g. 1 gigabyte per second as in Ethernet, or as slow as 110 bits per second via an RS232C interface. The term is sometimes applied to interfaces such as the RS232C and RS422 in which the data is transferred serially via one path, but some control signals can be transferred simultaneously via parallel paths. Compare parallel interface, serial-parallel.