3Com 3CR16709-91, 3CR16708-91 RJ-45 to RS-232, Adapter Cable, Panel. The pinout is shown below

B PIN-OUTS

RJ-45 to RS-232	An RJ-45 to DB-9 adapter cable is provided with the Switch for
Adapter Cable	connecting a management device to the RJ-45 console port on the rear
	panel. The pinout is shown below.
	Table 10 Pin assignments

RJ-45 Pin	Signal	DB-9 Pin	Direction
1	RTS	7	￿
2	DTR	4	￿
3	TxD	3	￿
4	DCD	1	￿
5	Ground	5	---
6	RxD	2	￿
7	DSR	6	￿
8	CTS	8	￿