The simplest method of alarm signalling is via a Digital Communicator which uses the audible bandwidth of a telephone line and signals to the Alarm Receiving Centre via a dialled call. The signal will not get through if the line is cut or engaged on another call. It is therefore recommended that a separate " Ex Directory" line is provided for the alarm.

RedCare is a more secure form of signalling since the BT line is continuously monitored at the local exchange and any signals are sent in the inaudible bandwidth of the telephone line. Phone calls can still be made whilst signals are being sent, although it is inadvisable for the line to be linked to a modem, fax or ansaphone which could cause interference.

This form of monitored signalling uses the Vodafone network to transmit signals to the Alarm Receiving Centre. There is no line to cut and no need to have a phone line. In many high security instances Paknet is combined with one of the two other forms of signalling above to ensure continuity of signals if the phone lines are cut or damaged.
Also suitable for isolated places were a telephone network is not available.