(At a time when mobile phones were in their infancy, and about the size of a housebrick, we ran an article on radio paging. The bleeper comes of age, we said...)
"The humble 'bleeper' has come a long way in recent years. Early pagers did no more than sound a tone to make it known that somebody, somewhere, wanted to talk to someone else. Paging today is much more sophisticated, but the basic principle remains the same. The pager itself is, in fact, a radio receiver. It receives signals sent out through dedicated radio paging networks operated by the pager companies.
"Today's pagers still emit a 'bleep', but most now have small screens on which a message can be transmitted either in words, or in a code using numbers. In those pagers, the bleep is there simply to alert the person to the fact that there is a message on the screen.
"Paging represents an effective and low-cost method of mobile communications for many people in the security industry and its low cost has a great deal of appeal in these financially difficult times.
"Compared with other mobile communications systems, pagers have one major drawback: they are strictly a one-way communications method. But if all you want to do is to let a service engineer know where to go for his next call, a pager will do the job quickly and efficiently. If you need to talk to the pager user, all you need do is send a message to 'phone the office'... The standard way of sending messages to such pagers is to telephone the paging company, give them the identification number of the pager that you wish to contact, and the message to be transmitted. The paging company takes care of the rest."
Location, location, location
(In a feature on the selection and siting of intruder detectors, we stressed the importance of location...)
"It is naturally important that the range and detection pattern of an intruder detector should match as closely as possible the actual environment in which it will be used. For example, putting a detector with a 20m range in a 5m square room is obviously bad practice, unless the unit offers complete adjustability within these limits.
"In large areas, it is possible to install several PIR detectors with overlapping protection patterns, since there is no interaction between the different sensors.
"Careful siting of detectors is absolutely vital, in order to minimise the risk of false alarms. With PIR detectors, most false alarms are caused by environmental factors such as strong heat or cold sources (eg open fires, radiators, heaters, air conditioners); sunlight falling on the unit; strong draughts; pets; and car headlights sweeping across the sensor. The person carrying out the initial site survey must therefore pay particular attention to any such factors which might trigger the unit into an alarm condition...
"Other points to remember are that PIR detectors are most sensitive to movement across the field of view than along it, and that corner mounting can give better room coverage than does wall mounting."
Punch drunk
(OK, so we all make mistakes, but we'd like to point out that the entire editorial team has changed since this bit of confusion in a test feature on the Abacus control panel from DA Systems...)
"Finally, the operator manual confuses the user when they try to change their code. It calls for the NO key to be punched once, in fact it needs to be punched twice! Finally, the operator manual confuses users when they try to change their code; it calls for the NO key to be punched, in fact it needs to be punched twice!"
(... so now who's confused?)
Source
Security Installer
