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See Also ... our FAQ on Radio Frequency Interference (RFI)

Table of Contents

1. Where does Interference originate?
2. What effect does Interference have on systems and data?
3. How can interference be controlled?

Where does interference originate ?

The short answer is: from the same place that spikes / surges come from - Lightning and man-made electrical equipment noise. Actually, Spikes and noise are very similar in nature; main difference being that Spikes are very much larger.

But there are other types of interference as well.

Radio stations, cellular phones, Citizen's Band and police radio, small office or household appliances, fluorescent lights, loose electrical connections, defective AC Power plugs, cords or sockets are among the many sources of electrical interference.

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What effect does Interference have on Systems and Data ?

Interference is aptly named. The name came from the earliest days of radio when so-called static from various sources "interfered" with radio reception. This concept carried forward to television and ultimately to computers.

Interference may cause erratic program operation; or it might cause errors in data processing (we've all heard the old anecdote of a $1,000,000 check being issued for a $1 refund).

In imaging - erratic, undesired color shifts might occur.

Communication may be disrupted or completely unintelligible.

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How can Interference be controlled ?

Two approaches are usually taken for interference control.

1. Apply suitable preventative measures to the interference source. Of course, to accomplish this, the interference source must be identified.

A good first step is to ensure regular, thorough electrical maintenance of equipment suspected of being the interference source. Be certain all electrical connections are securely tightened.

If quite certain this is the interference source, install suitable filtering and suppression to bring the interference under control. Usually a single socket (Industrial Grade) stand-alone power line filter-suppressor or a wire-in filter-suppressor solves the problem.

Unfortunately, it is often difficult, or impossible, to either identify the interference source.  If identified, access to the offending culprit is often unavailable or denied.  Fortunately, there is a second line of defense, as outline in the next step.

2. Apply interference control steps at equipment suffering interference (victim). This is usually the route taken because it is often impossible to isolate or work on the suspected interference source.

Depending on the amount and severity of interference the equipment encounters you could install an AC power line filter-suppressor, a KLEEN LINE^® Regulator-Isolator-Conditioner or a KLEEN LINE^® Isolation Transformer directly at the system. Industrial solutions would include Twist-Type Filter-Suppressors,  Wire-in Filter-Suppressors or Specialized Hi-Current Filter-Suppressors.

3. Modem interference, caused by Phone line interference,  is discussed in our Modem protection section. Models generally used to provide interference relief for modem interference  are PDS-11, PDS-11x2 and TURBO.

4. Network interference control is discussed in our Network & Data Line page. A wide array of products are presented for RS-232, RS-485, RS-422, 10Base-T, 100Base-T and Ethernet.

5. Video terminal, cable TV, Satellite receivers and computer monitor interference is discussed on the Video page. Solutions for many problems are offered. Cable modem protection and  audio/video hum bars or severe buzz cable isolators are available.

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See Also ... our FAQ on Radio Frequency Interference (RFI)

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