Apollo XP95 Intelligent Open-Area Visual Indicator has been developed for use in situations where there is a risk that sounders will not be heard. The device is powered directly from the loop and need no external power supply. It operates at 17 to 28VDC and is polarity sensitive. A nominal sound output of 100dBA is achieved at a current consumption of 5mA in the case of the sounder and 8mA for the sounder beacon. Many control panels will be able to drive up to 20 sounders and up to 15 sounder beacons per loop on average. The maximum number of devices that may be connected to a particular loop should, however, be determined by a loop loading calculation using the Apollo loop calculator. Since the alarm devices are intended for use in open areas, it is possible for more than one device to be audible at any given point in a building. For this reason, the operation of all may be synchronised by the control panel. All the alarm devices can be assigned group addresses as well as individual addresses, so that the functional options of the sounder are identical with those of the sounder control unit. The alarm devices have a base which is fitted to the mounting surface and wired as a first fix. The alarm devices will operate only with control equipment using the Apollo XP95 or Discovery protocol. The features of the Open-area alarm devices are available only when the device is connected to a control panel with the appropriate software.