Abstract: A computer-based display apparatus is provided for a fire alarm system having sensors located at various positions in a building or area. The display apparatus includes a computer with associated memory and display, as well as a facility for obtaining one or more screen images of the layout of the building or area from graphical representations of the layout, such as drawings, photographs or CAD generated data. The screen images are stored in memory for display on the computer display. The display apparatus also comprises a software facility for superimposing the positions of the sensors on the displayed layouts.