Radio alarm dual signalling.

Dual signalling is a method of alarm transmission that uses a mobile phone network and a telephone and/or IP path to transmit intruder, fire and personal attack signals at high speed from the protected premises to an Alarm Receiving Centre (ARC). It most commonly uses GPRS or GSM, a high-speed signalling technology used to send and receive ‘packets’ of data, with a telephone line in addition. The option of IP is not used as frequently due to issues with installation and configuration as a high level of I.T expertise is often required in addition to alarm installation knowledge.

A dual signalling communication device is attached to a control panel on a security installation and is the component that transmits the alarm to the ARC. It can do this in a number of different ways, via the GPRS radio path, via the GSM radio path or via the telephone line/or IP if that has been chosen. These multiple signalling paths are all present and live at the same time backing each other up to minimise exposure of the property to intruders. Should one fail there is always one form of back up and depending on the manufacturer chosen up to three paths working simultaneously at any one time. Prior to the availability of dual signalling systems, police and keyholders were often called out to the premises because of an alarm signal on the telephone path only to discover that it was a network fault and not a genuine alarm

Dual paths allow distinction between hardware failures and a genuine attack on the alarm. This helps eliminate false alarms and unnecessary responses. Dual signalling has helped considerably with the restoration of Police response as in an instance where a phone line is cut as the dual signalling device can continue to send alarm calls via one of its alternative paths either confirming or denying the alarm from the initial path.

In the UK, CSL DualCom Ltd pioneered dual signalling in 1996. In doing so, the company offered the first credible alternative to existing alarm signalling while setting the current standard for professional dual path security monitoring. Dual signalling is now firmly regarded as the standard format for alarm signalling and is duly specified by all of the leading insurance companies.