16 C HAPTER 1: INTRODUCING THE SWITCH 3300 FXExpansion ModuleSlotYou can use this slot to install an Expansion Module; for example, a100BASE-FX Module that provides an additional high-speed link, or aMatrix Module that provides four matrix ports for stacking Switch unitstogether. 3Com provides a range of Expansion Modules; contact yoursupplier for availability. For more information about Matrix Modules, see“Stacking Units” on page 26.When an Expansion Module is not installed, ensure the blanking plate issecured in place.Matrix Port The matrix port allows you to:n Stack the Switch with another unit in the Switch 1100/3300 familyusing a single Matrix Cablen Stack the Switch with up to three other units in the Switch 1100/3300family, if one of the units has a Matrix Module installedFor more information about the role of the matrix port, see “StackingUnits” on page 26.