These diagrams are made from copying modtaps I have found that actually worked, not from copying pieces of other pages elsewhere (such as cisco).

Cisco 2500 series routers
RJ45 pin	db25 pin	db9 pin	pin name
1	5	8	CTS
2	8	1	DCD
3	3	2	RXD
4 & 5	7	5	GND
6	2	3	TXD
7	20	4	DTR
8	4	7	RTS
On the modtap that I found, RJ45 pins 4 and 5 were both put to db25 pin 7. If you can't put them both there, 4 by itself seems to work just fine. You shouldn't need a null modem with either of these wirings.
Xylogics Annex
RJ45 pin	db25 pin	db9 pin	pin name
3	3		RXD
5	2		TXD
6	7		GND
Null modem needed for this modtap. On the db25 side, pins 4, 5, 6, 8, and 20 (RTS, CTS, DSR, DCD, and DTR) were all wound together. On the RJ45 side, pins 1, 2, 4, 7, and 8 were all simply clipped.

SO...as Cisco says...

So where the heck is Pin 1?

ethernet crossover wiring (fyi)