DB9 female to DB25 female serial port pin definitions: DB9 pin 1 to DB25 pin 8, DB9 pin 2 to DB25 pin 3, DB9 pin 3 to DB25 pin 2, DB9 pin 4 to DB25 pin 20, DB9 pin 5 to DB25 pin 7, DB9 pin 6 to DB25 pin 6, DB9 pin 7 to DB25 pin 4, DB9 pin 8 to DB25 pin 5, DB9 pin 9 to DB25 pin twenty two.