Connects any RS232 serial device with DTE DB9 to PC with DB25 serial port. This null modem adaptor also allows you to transfer files between two computers using its DB25 or DB9 serial port along with a DB25 or DB9 straight thru cable as well as all RS232 DTE to DTE connections. Pin-Out: 2-2 / 3-3 / 4-1,6,8 / 5,6,8 - 7 / 7-5. (Connectors: DB9 Female to DB25 Female)