RS-232 formally defines the signals connecting between a Data Terminal Equipment (DTE) and a Data Circuit-terminating Equipment (DCE).
RS-232 defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-terminating Equipment Employing Serial Binary Data Interchange, issued in 1997.