Description: In a simulcast system base stations must have a 1PPS pulse. This alarm should be disabled for other systems. It is not applicable to receive only base stations. The alarm warns that the base station isn't receiving a 1PPS pulse. If the base station loses the pulse but is still receiving its external reference, it phase-locks its transmit clock to the external frequency reference in order to maintain synchronization. This is called Holdover mode and is a temporary measure. When the holdover duration expires the base station becomes unsynchronized. The 'Simulcast unsynchronized' alarm under 'Reciter' below indicates whether the base station is synchronized for simulcast operation. The 'Receiver unsynchronised' alarm in this section indicates whether the base station receiver is synchronized. Range: unavailable(0), cleared(1), raised(2), disabled(3)