Serial port Loopback (9 CheckIt) pinout

9 pin D-SUB female connector layout
9 pin D-SUB female connector at the computer


Used to verify that a port is working. This one works with CheckIt.

Name Pin Pin Name
CD 1 6 DSR
CD 1 9 RI
RXD 2 3 TXD
DTR 4 6 DSR
RTS 7 8 CTS