Surgical stapling instruments include mechanisms for identifying and/or deactivating stapler cartridges for use with the instruments. The stapling instrument includes a drive member for actuating a staple cartridge and a locking member movable from a disabled position permitting distal translation of the drive member through a staple firing stroke, to a locking position inhibiting distal translation of the drive member through the staple firing stroke. The staple cartridge may include a switch movable in a lateral direction to either maintain the locking member in the disabled position or to allow the locking member to move into the locking position. The instrument may further include a stapler cartridge including an annular pin configured to be engaged by a drive member at a an axial position to create a detectable resistance for reload detection by a control unit to identify the type of stapler cartridge present in the surgical stapling instrument.