Nortel Ethernet Routing Switch 4500 series stacking 55Unit Select switchUse the Unit Select switch to designate a switch in the stack as the baseunit. Slide the Unit Select switch to the right to designate a switch as thebase unit. You can designate only one switch in a stack as the base unit;that is, with the switch in the base unit position. For all other switches in thestack, the Unit Select switch must be in the left position.The base unit designation for a switch is also displayed on the front panelLED display (see "Switch LED state indicators" (page 44)).Cascade Down connectorUse the Cascade Down connector to connect a switch to the next unit in thestack through a cascade cable. Connect the other end of the Cascade Downcable to the Cascade Up connector of the next switch in the stack. A returncable from the Cascade Down connector of another unit to the Cascade Upconnector of the first unit completes the stack connection (see "Simplifiedstacking diagram" (page 56)and"Connecting cascade cables" (page 56)).ATTENTIONTo create a stack connection, order the appropriate Nortel Ethernet RoutingSwitch 4500 Series cascade cables to ensure fail-safe stacking. A 1.5 footstacking cable is included with the switch. For stacking three or more units(maximum 8 units per stack), order the 5’, 10’, 14’ or 16.4’ cables as applicable.Cascade Up connectorThe Cascade Up connector provides an attachment point that accepts acascade cable connection from another unit in the stack. A return cable fromthe Cascade Down connector of one switch to the Cascade Up connectorof an adjacent switch completes the stack connection. See "Simplifiedstacking diagram" (page 56) and "Connecting cascade cables" (page 56)."Simplified stacking diagram" (page 56) illustrates a simple, two-switchstack connection.Nortel Ethernet Routing Switch 4500 SeriesInstallation GuideNN47205-300 (322811-B) 03.01 Standard5.1 19 November 2007Copyright © 2007, Nortel Networks.