Sendon UPS-500 dumb cable

9 pin D-SUB male connector to the UPS

UPS Signal Name	DB-9 Male (UPS end)	DB-9 Female (PC end)	PC Signal Name
AC Fail	2	8	CTS, connected by R 1k8 to pin 7(RTS)
Batt Low	5	1	DCD, connected by R 1k8 to pin 8 (CTS). Connected by R 1k8 to pin 7(RTS)
Shutdown	6	R=10k, 4	DTR
Common	4,7	3	TxD

9 pin D-SUB female connector to the computer