A printing cartridge (1230) includes a housing (1231). An actuating formation (1240) is positioned on the housing and is capable of actuating a number of capacitive sensors (1238) in an array of such sensors. The actuating formation is configured to represent data relating to at least one of: a serial number of the cartridge, a media and a media colorant, so that the capacitive sensors, when actuated, together generate a signal carrying such data