3Com SUPERSTACK 3 3870 Series Getting Started Manual

Also see for 3CR17450-91: Datasheet Getting started guide

Contents

26 CHAPTER 2: INSTALLING THE SWITCHFor full redundancy, the unit requires two Type 3 Power Modulescombined using a Type 3 Y-Cable (part number 3C16077).WARNING: If you are connecting the Switch to a Type 3 Power Module,read the Safety Information section in the Type 3 Power Module UserGuide.CAUTION: The Switch can only use a SuperStack Advance RedundantPower System output.Choosing the CorrectCablesAll of the ports on the Switch are Auto-MDIX, that is they have across-over capability. These ports can automatically detect whether tooperate in MDI or MDIX mode. Therefore you can make a connection toone 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 asMDIX (cross-over). If you want to make a connection to another MDIXport, you need a cross-over cable. Many ports on workstations andservers are configured as MDI (straight-through). If you want to make aconnection to an MDI port, you need to use a standard straight-throughcable. 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 ifauto-negotiation is disabledCross-over Cable Straight-through CableSwitch to Switch(MDIX to MDIX) ✓ ✕Switch to Hub(MDIX to MDIX) ✓ ✕Switch to PC (NIC)(MDIX to MDI) ✕ ✓DUA1745-0AAA02.book Page 26 Monday, August 9, 2004 11:51 AM