serial line

In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time (contrast parallel port). Throughout most of the history of personal computers, data transfer through serial ports connected the computer to devices such as terminals or modems. Mice, keyboards, and other peripheral devices also connected in this way.
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Wires which connect two serial ports carrying serial data consisting of sequential bits represented by one of two voltages.
A common electrical specification for the signals on a serial line is RS-423.
ftp://ftp.acorn.co.uk/pub/documents/appnotes/231-245/234.ps.
(1995-02-02)