3Com 3CR17661-91 manual Choosing, Correct Cables, Transceiver, Your Switch, Cable. See Table

28CHAPTER 2: INSTALLING THE SWITCH

Removing an SFP	If you wish to remove the transceiver (it is not necessary to power-down
Transceiver	your Switch):

1Disconnect the cable from the transceiver.

2Move the wire release lever downwards until it is pointing toward you.

3Pull the wire release lever toward you to release the catch mechanism; the transceiver will then easily slide out.

Choosing the	All of the ports on the Switch are Auto-MDIX, that is they have a
Correct Cables	cross-over capability. These ports can automatically detect whether to
	operate in MDI or MDIX mode. Therefore you can make a connection to
	one of the ports with a straight-through (MDI) or a cross-over cable
	(MDIX).
	The Auto-MDIX feature only operates when auto-negotiation is enabled.
	If auto-negotiation is disabled, all the Switch ports are configured as
	MDIX (cross-over). If you want to make a connection to another MDIX
	port, you need a cross-overcable. Many ports on workstations and
	servers are configured as MDI (straight-through). If you want to make a
	connection to an MDI port, you need to use a standard straight-through
	cable. See Table 8.
	3Com recommends that you use at least Category 5 twisted pair
	cable—the maximum segment length for this type of cable is 100 m (328
	ft.).

Table 8 Cables required to connect the Switch to other devices if auto-negotiation is disabled

Cross-over Cable Straight-through Cable

Switch to Switch (MDIX to MDIX)

Switch to Hub (MDIX to MDIX)

Switch to PC (NIC) (MDIX to MDI)

✓✕

✓✕

✕✓