Serial Port

Serial Pinouts (D9 and D25 connectors)
D-Type 9	D-Type 25	Abbreviation	Fullname
Pin 3	Pin 2	TD	Transmit Data
Pin 2	Pin 3	RD	Receive Data
Pin 5	Pin 7	SG	Signal Ground
Pin 4	Pin 20	DTR	Data Terminal Ready
Pin 6	Pin 6	DSR	Data Set Ready
Pin 1	Pin 8	CD	Carrier Detect
Pin 7	Pin 4	RTS	Request To Send
Pin 8	Pin 5	CTS	Clear To Send
Pin 22	Pin 9	RI	Ring Indicator

Null Modem Wiring Diagram

Loopback Plug Wiring Diagram

More Information about the RS-232 at

Interfacing the PC

Roedy Greens "More Than You Wanted To Know About RS232C"

©1999 Martin Hachenberg

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