The Joy of Troubleshooting
Testing Tips and Shortcuts
In earlier days, for the most part troubleshooting consisted of knowing basic direct current (DC) and relay theory. Today, security system troubleshooting can cover many technology areas, such as the optics of video and fiber; radio frequency spectrums; basic physics (e.g. temperature and light); computer hardware and networks; and computer software and operating systems.
Still, the basic testing tool for all technicians is a good, dependable digital volt meter (DVM). This tool, along with a firm understanding of DC 
theory, will be the basic foundation for any alarm circuit troubleshooting.
It is recommended some options, such as a latching continuity audible tester, be part of your DVM. This will help with finding those illusive intermittent alarm circuit interruptions so often referred to in the industry as swingers.
Today’s technician has to become familiar with a new generation of testing equipment that combines many troubleshooting features into one device.
A good example is the Tri-Porter™ from JDSU / Test-Um. This device is capable of testing voice (telephone), data (Ethernet networks) and video (RF detection) circuits. This is like combining a phone, network connectivity, tone generator, cable tester/verifier, tone detector/cable finder and coax mapper in two small devices.
The swingers mentioned above are one of the most problematic security system malfunctions. They can be something as simple as a loose wire that will make or break an alarm circuit when there is a slight vibration or change in temperature, which tends to make objects expand and contract.
Trying to find a source to the problem can be very frustrating. Techs often prefer using (sometimes homebrewed) test devices that have a high-speed audible latching circuit. This will allow the slightest false alarm-producing intermittent circuit connection to trigger an audible test alert.
One testing technique for finding problems in large series circuits with multiple door/window contacts is the “divide-and-conquer” method. Divide the circuit in half, shunt (short) one of the halves and see if the other side presents the problem. Then divide the bad circuit side again and do the same. Keep dividing it in half until you get down to the bad device.
A more sophisticated testing device that can sometimes help with long-term intermittent problems is a data logger. In the past, these devices were very expensive and typically only used by engineers. However, there are now low-cost USB-type standalone data recorders available from companies like Pico Technology that can record circuit voltages during long time durations.
Some modules have digital outputs that can be used to trigger other devices as well. This data can then be fed into accompanying software to help analyze a trouble pattern. Additionally, there are DVMs, such as the Fluke 289, that come with logging capability. Any recording capability is additionally handy in that you may need this data to prove the intermittent problem is caused by the customer’s action and 
is not a faulty system component.
Troubleshooting now includes testing devices that can analyze new network technology, such as Power over Ethernet (PoE). PoE technology is particularly popular with security devices such as IP cameras.
A technician, again with a good understanding of DC circuit theory (Ohm&rs
quo;s Law) and a tester such as the ByteBrothers Power Panel, can get an accurate reading of the voltage available to run a PoE IP camera. There is an inline version that provides an accurate circuit reading and a DSL-sensing model as well.
Since all security systems deal with battery backup, an essential part of a troubleshooting toolkit for alarm systems is a battery tester.
Companies such as ELK Products Inc. and Act Meters Ltd. have testers that not only reveal the present status of a battery, but also how much life is expected from that battery. This can help predict when a battery should be replaced. Battery testing should be an important part of any alarm system service call.
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