While a gross amount of equipment is needed to supply a professional countermeasures team (6 and 7 figure sums are often quoted), a handful of readily available tools will suffice for basic home-brew inspections. Due to the sheer volume of insruments used on a TSCM sweep, some are not currently discussed.
Time Domain Reflectometers (TDRs) are a specific kind of oscilloscope, designed to locate anomolies on cables. TDRs work by sending a pulse of energy down the line and measuring the energy of the returned signal and the time it took to return (rather like RADAR), and displaying the results on a CRT (on a good graphical TDRs) or as distance to the anomoly (on a cheaper numeric TDRs). The primary use of TDRs in countermeasures work is to locate wirtaps and other hardwired devices. An excellent tutorial on TDR analysis can be found at Riserbond Industries, and serious instruction in time domain reflectometry for countermeasures applications can be acquired at most security schools.
Multi meters (both DMMs and VOMs) are the backbone of a countermeasures sweep. These meters are used to make a variety of measurments on just about everything that will sit still, though they see the most exercise on telephone surveys and checks for hardwired devices. If you're unsure about how to use a multimeter, any book of basic electronics can explain it.
Induction probes are wand-like devices used in the telecommunications industry to determine the status of traffic on the line without having to worry about disturbing line traffic. On a formal sweep, induction probes will be used in conjunction with trace tone generators to identify specific pairs. Less formal inspections will use an induction probe as an all-purpose amplifier to identify hook-swtch compromises and hardwired devices.
Line amplifiers are a heavily used tool in countermeasures sweeps. These amplifiers are used to detect hardwired threats and telephone attacks by connecting them to any wires in thearea and listening for room audio. A professional countermeasures amp will usually incorporate a few extra features such as variable impedence and gain as well as a tone generator to activate certain devices.
Lineman's handsets are used for accessing telephone lines for test purposes. If you expect to be dealing with data lines, a buttset with the ability to monitor data will be handy. Harris markets test sets for data with "Data Safe" or "Data Lockout" features.
Frequency counters are used to determine the operating frequency of a radiated signal.
Oscilloscopes are used for a variety of things on countermeasures sweeps. They are typically used to ferret out hard-wired threats, and to provide additional information about RF threats when connected to a search receiver.
Because a good deal of TSCM involves looking for devices that are emmitting radio waves, a good receiver is an absolute must. Relatively inexpensive scanners are sometimes seen, though usually during an in-place monitoring. For a sweep, commercial (HP and Avcom) spectrum analyzers and specialized countermeasures receivers (Scanlocks and Eagles) are usually the core RF detectors.
This particular kit is far from perfect, but it will allow you to make a basic inspection and locate simpler devices.
A test set of some sort will allow you to monitor line traffic and preform certain tests on a line.
Being able to make noise is important. A blasting radio will cover up the sound of you moving furniture around, turn on voice activated devices, and give you something to listen for when trying to locate your line.
Having a good collection of knives, screwdrivers and punches wll be really handy. A Leatherman or other similar multi-tool is generally recomended by the experts, though a knock-off swiss army knife will suffice.
Expect to be digging around in telco splicing enclosures, under furniture, in basements, and all sorts of other dark places during an inspection.
The meter is the core of telephone sweeps, and will be used to help locate many other devices. Voltage, resistance and capacitance all need to be measured in order to assist in your sweep.
A small mirror will let you see behind wiring blocks, under furniture and doors and into other tight spaces.
A pick of some sort is incredibly useful when sorting though wires.
This tool will open NIDs and many telco cabinets.
Induction probes are the neatest thing since sliced bread. These devices will alow you to hear traffic on a line without having to clip in with a test set, making split line location or hookswitch compromises easy.
Are carrier-current devices are in use? A good carrier current receiver should detect it.
A frequency counter is invaluable for finding radio traffic, including surveillance transmitters.
Keeping a pen and paper handy at all times will serve you well, as you'll likely have to write down cable numbers, locations etc; as well as local test numbers and PIC color codes.
The equipment above can be upgraded for slightly more money in many places. The radio can be replaced by a test tone generator, which can further be upgraded through the addition of a frequency multiplier to raise the tone frequency to 6000 hz (effectively making it silent over the phone).