Revisions in ETSI standards could cause alarm for emergency button users

05-10-2011

A recent revision of an ETSI (The European Telecommunications Standards Institute) standard, which governs most licence exempt telemetry applications, has caused concern amongst manufacturers of wireless communications systems for social alarms.

Social alarms are used by older people and those with a physical disability or a degenerative illness to communicate with support services in an emergency.  Often worn around the neck or installed as pull chords, these products enable vulnerable people to live independently in the knowledge that one press of a button will connect them to support services.  One of the larger social alarm service providers, Age UK, receives an average of 750,000 calls per year in the UK from such devices.

Social alarms rely on short range wireless communications between the alarm unit (as worn around the neck of a user) and the household fixed line telephone system.  When the button is pressed, the telephone system automatically generates a phone call to a support centre where the user can be helped or support dispatched.  This wireless connection is subject to an ETSI standard EN300 220.  Recently the standard was revised meaning that social alarm products no longer have to meet every aspect of the previous standard.  Critically, under the new standard, social alarms are exempted from rigorous intermodulation requirements. 

Alan Wood, Managing Director of Wood & Douglas, a specialist wireless communications manufacturer based in the UK commented: “Intermodulation is rarely desirable in radio or audio processing as it generated emissions which can create minor to severe interference.  In the home environment there are numerous potential sources for wireless interference.  To date social alarm systems have been subject to specific intermodulation requirements, which ensured that interference did not impact the performance of the product, but the new standard removes this requirement.”

Some wireless specialists have suggested that this will lead to “system on a chip” solutions that, whilst cheaper to manufacture, will not provide the same level of reliability for social alarms.  Wood continued: “The revision of the standard enables chip manufacturers to embed short range wireless on the chip, providing a potentially less robust solution.  This could cause false alarms through wireless interference or, in the worst case, even the failure of an emergency call to be received.”