Now we must look at the telephone system. What is the quality of service you receive?
Is there noise on the line? Can you describe it? There is noise within normal hearing range and there is noise below and beyond normal hearing ranges.
Does your telephone ring during a thunderstorm?
When talking to someone can you hear others, not a party to your conversation, talking? Is that speech clear or garbled?
Most telephone service has been vastly improved in recent years to support computerized traffic and the like. There may be, from time-to-time, types of interference that could play havoc on an alarm system especially one not containing discriminatory circuits designed to filter out all signals not being sent from the monitor panel to the central station and back. Bottom line, electricity is still the mode.
In my neighborhood we have fiber optic lines. Fiber optic cable is a communications messenger. It faithfully carries as light energy, all the converted electromagnetic intelligence data, to include noise, from a transmitter to a receiver where it is converted back into electromagnetic intelligence data again. It should be remembered noise is also intelligence -- unwanted intelligence. Electricity and grounding get two strikes at the system at two different locations: on the transmitted side and on the received side.
This may be a lot of questions, and perhaps a more exhaustive site survey than you had planned on, but remember that all these factors can affect an electronic security system.
[Editor's note: In the next part of this series, Bill Warnock takes a look at what these factors mean in terms of false alarms.]