3. ELECTROMAGNETIC
INTERFERENCE AND
WARNINGS
Powered wheelchairs may be susceptible
to electromagnetic interference (EMI),
which is interfering electromagnetic
energy (EM) emitted from sources such as
radio stations, TV stations, amateur radio
(HAM) transmitters, two-way radios, and
cellular phones. The interference (from
radio wave sources) can cause the power
chair to release its brakes, move by itself,
or move in unintended directions. It can
also permanently damage the power
chair control system. The intensity of the
interfering EM energy can be measured in
volts per meter (V/m). Each power chair can
resist EMI up to a certain intensity. This is
called its “immunity level.” The higher the
immunity level, the greater the protection
will be.
There are a number of sources of relatively
intense electromagnetic fields in the
everyday 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 warnings listed below, your
risk to EMI will be minimized.
Netti Mobile, degree of protection: IPX4.
Netti Mobile is EMC approved.
It is very important that you read this
information regarding the possible
eects of Electromagnetic
Interference on your power chair.
The sources of radiated EMI can be broadly
classified into three types:
• Hand-held portable transceivers
(transmitters-receivers) with the antenna
mounted directly on the transmitting unit.
Examples include: citizens band (CB)
radios, “walkie talkie,” security, fire, and
police transceivers, cellular telephones,
and other personal communication
devices.
Some cellular telephones and similar
devices transmit signals while they
are ON, even when not being used.
• Medium-range mobile transceivers, such
as those used in police cars, fire trucks,
ambulances, and taxis. These usually have
the antenna mounted on the outside of
the vehicle.
• Long-range transmitters and transceivers
such as commercial broadcast transmitters
(radio and TV broadcast antenna towers)
and amateur (HAM) radios.
Other types of hand-held devices, such
as cordless phones, 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 to your
power chair.