Emergency alarm systems - Quality
Quality varies significantly in the security equipment market. Because there are no insurance standards etc. for these types of devices, the next thing to look for in terms of finding a quality product is SBD (Secured by Design) accreditation. Secured by Design is a scheme operated by the Association of Chief Police Officers.
The scheme tests and evaluates security products and awards accreditation to specific products that they feel are highly reliable. These products, out of interest, are the only products the police are allowed to recommend to the public. If a product has SBD status, it or its advertising will display the SBD logo. You can also search the SBD product list here.
If you cannot find an SBD accredited emergency alarm system that you feel suits your needs, then there are a lot of battery powered SMS / GSM alarm systems on the market. Any of these could be used in circumstances where no power or communication lines are available, but watch out. If you think that buying a battery powered SMS security system for £99.99 is going to reliably secure your clients property and possessions, then please think again.
A well designed and well built stand-alone battery powered PIR like the Mobeye i110 or Mobeye Argos with inbuilt SMS communications will cost upwards of £200 and larger systems that allow multiple PIRs to be wirelessly connected to them such as RDAS systems will be upwards of £500. These are the sort of prices you should be looking at. If a device is significantly cheaper than this, you are very likely to get an unreliable product and that could cost your clients dear in the long run if it fails to protect their premises.