This diagram maps a DB9 to RJ45 Adapter in such a way to emulate a rollover cable, using a standard, Straight-through, CAT 5 patch cable

DB9	Wire 					RJ45
Pins	Color					Pin #

1	N/C					Blue
2	Black					Orange
3	Yellow					Black
4	Brown					Red
5	Green and Red (tie them together)	Green
6	Orange					Yellow
7	White					Brown
8	Blue					White
9	N/C					  -