Simplex 4100-1276 8 Red Pluggable LED ModuleAnnunciation Options. 4100ES 4100U fire alarm panels support a variety of switch input and LED status indicators to complement the information and controls available at the operator interface. These modules provide a convenient interface efficiently packaged onto the front panel space of the cabinet bay. Additionally, the panel mounted printer can conveniently record system status without requiring a separately located printer. Easy Interface.