Standard DB9 and DB25 Pinouts

Name        25-pin         9-pin
---------------------------------------------------------
TxD           2             3       transmit data
RxD           3             2       receive data
RTS           4             7       request to send (power)
CTS           5             8       clear to send
DSR           6             6       data set ready
GND           7             5       ground
DCD           8             1       data carrier detect(signal)
DTR          20             4       data terminal ready