An alarm system installed in a region to be monitored, the alarm system comprising: a control panel; a graphical interface (122,140,142) in communication with the control panel for displaying information on a graphical user interface device, a plurality of devices (130, 130') of the alarm system; the devices being in a plurality of locations in the region; each of the devices being identified by the control panel by means of a device identifier, the identifiers provided on the graphical user interface device; and wherein the positions of the devices in the region are provided on a plan (110, 110', 510) on the graphical user interface device; wherein the graphical interface (122,140,142) is configured to provide an interactive screen, that screen providing: a display of the devices; the graphical user interface being further configured to receive input from a user to associate devices with the positions of devices on the plan so as to activate the functionality of each device in the alarm system by allocating a respective unique system address to each respective device using the interactive screen; characterised in that the graphical user interface device is a mobile graphical user interface device and is equipped with a positioning system to identify the geographic position of the mobile graphical user interface device in the region, and wherein the geographic position of the interface is displayed on the plan provided on the graphical user interface device. a control panel; a graphical interface (122,140,142) in communication with the control panel for displaying information on a graphical user interface device, a plurality of devices (130, 130') of the alarm system; the devices being in a plurality of locations in the region; each of the devices being identified by the control panel by means of a device identifier, the identifiers provided on the graphical user interface device; and wherein the positions of the devices in the region are provided on a plan (110, 110', 510) on the graphical user interface device; the devices being in a plurality of locations in the region; each of the devices being identified by the control panel by means of a device identifier, the identifiers provided on the graphical user interface device; and wherein the positions of the devices in the region are provided on a plan (110, 110', 510) on the graphical user interface device; wherein the graphical interface (122,140,142) is configured to provide an interactive screen, that screen providing: a display of the devices; the graphical user interface being further configured to receive input from a user to associate devices with the positions of devices on the plan so as to activate the functionality of each device in the alarm system by allocating a respective unique system address to each respective device using the interactive screen; a display of the devices; the graphical user interface being further configured to receive input from a user to associate devices with the positions of devices on the plan so as to activate the functionality of each device in the alarm system by allocating a respective unique system address to each respective device using the interactive screen; the graphical user interface device is a mobile graphical user interface device and is equipped with a positioning system to identify the geographic position of the mobile graphical user interface device in the region, and wherein the geographic position of the interface is displayed on the plan provided on the graphical user interface device.