GF0600055RevA06, October 006
Everest Lite Owner's Manual
ELECtROMAGnEtIC IntERFEREnCE (EMI) FROM RAdIO WAVE sOuRCEs
It is very important that you read this information regarding the possible effects of elec-
tromagnetic interference on your Everest & Jennings® Everest Lite power wheelchair.
Powered wheelchairs may be susceptible to electromagnetic interference (EMI), which
is interfering electromagnetic (EM) energy emitted from sources such as radio stations,
TV stations, amateur radio (HAM) transmitters, two-way radios, and cellular telephones.
The interference (from radio wave sources) can cause the powered wheelchair to release
its brakes, move by itself, or move in unintended directions. It can also permanently
damage the powered wheelchair's control system. The intensity of the interfering EM
energy can be measured in volts per meter (V/m). Each powered wheelchair can resist
EMI up to a certain intensity. This is called its “immunity level”. The higher the immunity
level, the greater the protection. At this time, current technology is capable of achieving
at least a 20 V/m immunity level, which would provide useful protection from the more
common sources of radiated EMI.
This powered wheelchair model has an immunity level of 20 V/m.
Be aware that using different components, adding accessories, or modifying the powered
wheelchair may change the immunity level.
There are a number of sources of relatively intense electromagnetic fields in the every-
day environment. Some of these sources are obvious and easy to avoid. Others are not
apparent and exposure is unavoidable. However, we believe that by following the warn-
ings that follow, your risk to EMI exposure will be minimized.
The sources of radiated EMI can be broadly classified into three types:
1) Hand-held portable transceivers (transmitters-receivers) with the antenna mounted
directly on the transmitting unit. Examples include: citizens band (CB) radios, “walkie
talkies”, security, fire, and police transceivers, cellular telephones, and other person-
al communication devices.
Note: Some cellular telephones and similar devices transmit signals while they are on,
even when not being used;
2) Medium-range mobile transceivers, such as those used in police cars, fire trucks, am-
bulances, and taxis. These usually have the antenna mounted on the outside of the
vehicle; and
3) Long-range transmitters and transceivers, such as commercial broadcast transmit-
ters (radio and TV broadcast antenna towers) and amateur (HAM) radios.
Note: Other types of hand-held devices, such as cordless telephones, laptop computers,
AM/FM radios, TV sets, CD players, and cassette players, and small appliances, such
as electric shavers and hair dryers, so far as we know, are not likely to cause EMI
problems with your powered wheelchair.
