APC UPS control system manual RS232 Wiring and Signal Conventions

action = ioctl(TIOMCBIS, DTR) set DTR (kills power)

RS232 Wiring and Signal Conventions

DB-25 Pin #	DB-9 Pin #	Name	DTE-DCE Description
1	—	FG	– Frame Ground/Chassis GND
2	3	TD	–> Transmitted Data, TxD
3	2	RD	<– Received Data, RxD
4	7	RTS	–> Request To Send
5	8	CTS	<– Clear To Send
6	6	DSR	<– Data Set Ready
7	5	SG	–— Signal Ground, GND
8	1	DCD	<– Data Carrier Detect
9	—	—	– Positive DC test voltage
10	—	—	– Negative DC test voltage
11	—	QM	<– Equalizer mode
12	—	SDCD	<– Secondary Data Carrier Detect
13	—	SCTS	<– Secondary Clear To Send
14	—	STD	–> Secondary Transmitted Data
15	—	TC	<– Transmitter (signal) Clock
16	—	SRD	<– Secondary Receiver Clock
17	—	RC	–> Receiver (signal) Clock
18	—	DCR	<– Divided Clock Receiver
19	—	SRTS	–> Secondary Request To Send
20	4	DTR	–> Data Terminal Ready
21	—	SQ	<– Signal Quality Detect
22	9	RI	<– Ring Indicator
23	—	—	–> Data rate selector
24	—	—	<– Data rate selector
25	—	TC	<– Transmitted Clock

Pin Assignment for the Serial Port (RS-232C), 25-pin and 9-pin, Female End

13	1	5		1
_______________________________		_______________
\	. /	\		/	RS232-connectors
\	. /	\ . . . .		/	looking into the
---------------------------		-----------			end of the cable.
25	14	9	6

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