The system is controlled from the Nurse Station Unit (NSU) which displays the type of call – standard patient, bathroom, emergency (staff to staff) and cardiac (staff to staff) – and the location. A speech handset can be provided for direct communication between nurse and patient, and staff to staff, and a series of sounders and lights further identify the call type and its location. Optional features on the NSU include staff presence indication, intruder indication alarm, drug cupboard door open indication and an interface with a paging system.