Main Objectives of this connector is to allow full duplex communication between peripherals that uses such connector such PIC Demo board, ICD2 Debugger etc. The RS32 connector pin layout is show in the figure below.

FIGURE: RS32 connector pin layout

RS232 single-ended connector was introduced in 1962, and despite rumors for its early demise, has remained widely used in today's industry. The RS232 signals are represented by voltage levels with respect to a system common (power / logic ground). The "active" state known as (SPACE) signal level is positive with respect to common, and the "idle" state known a (MARK) signal level is negative with respect to common. RS232 has numerous handshaking lines (primarily used with modems), and also specifies a communications protocol.
The output signal level usually swings between +12V and -12V. The "dead area" between +3v and -3v is designed to absorb line noise. This means RS32 circuits can be powered by 5 VDC directly, however, this may reduce RS232 signals transmitted/received dramatically.