26 C HAPTER 2: INSTALLING THE SWITCHStacking Units Units in the Switch 1100/3300 family can be stacked together and thentreated as a single manageable unit with one IP address.The Matrix Port on the rear of the Switch allows you to connect twoSwitch units back-to-back. For this you need a Matrix Cable (part number3C16965). Contact your supplier for details.The Switches in a stack are numbered 1 to 4, from the bottom up, formanagement purposes. The SuperStack 3 Switch 3300 MM will alwaysbe identified as Unit 1 and should therefore be positioned at the bottomof the stack.Stacking Two Units You can stack two Switch units with a single Matrix Cable. To do this:1 Power-off both units.2 Arrange the units as required. They can be rack-mounted orfree-standing; if you choose to have them free-standing, remember toposition the rubber feet as detailed in “Placing Units On Top of EachOther” on page 25. When positioning the units, note that Matrix Cablesare 1m (3.28ft) long.3 Connect one end of the Matrix Cable to the Matrix Port of the topSwitch, and the other end to the Matrix Port of the lower Switch (SeeFigure 8).4 If you use the management software of the units: Ensure that both units have the same version of managementsoftware Ensure that you re-configure the stack-wide features on both unitsFor more information about management software, see “Managing theSwitch” on page 32.