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for convenience and comfort. These systems reduce the
absorption of RF energy in the head because the USB
dongle, which is the source of the RF emissions, will not
be placed against the head. On the other hand, if the
USB dongle is mounted against the waist or other part
of the body during use, then that part of the body will
absorb more RF energy. Wireless USB dongles
marketed in the U.S. are required to meet safety
requirements regardless of whether they are used
against the head or against the body. Either
configuration should result in compliance with the
safety limit.
Do wireless USB dongle accessories that claim
to shield the head from RF radiation work?
Since there are no known risks from exposure to RF
emissions from wireless USB dongles, there is no
reason to believe that accessories that claim to shield
the head from those emissions reduce risks. Some
products that claim to shield the user from RF
absorption use special USB dongle cases, while others
involve nothing more than a metallic accessory
attached to the USB dongle. Studies have shown that
these products generally do not work as advertised.
Unlike “hand-free” kits, these so-called “shields” may
interfere with proper operation of the USB dongle. The
USB dongle may be forced to boost its power to
compensate, leading to an increase in RF absorption. In
February 2002, the Federal trade Commission (FTC)
charged two companies that sold devices that claimed
to protect wireless USB dongle users from radiation
with making false and unsubstantiated claims.
According to FTC, these defendants lacked a reasonable
basis to substantiate their claim.
What about wireless USB dongle interference
with medical equipment?
Radio frequency energy (RF) from wireless USB dongles
can interact with some electronic devices. For this
reason, FDA helped develop a detailed test method to
measure electromagnetic interference (EMI) of
implanted cardiac pacemakers and defibrillators from
wireless teleUSB dongles. This test method is now part
of a standard sponsored by the Association for the
Advancement of Medical instrumentation (AAMI). The
final draft, a joint effort by FDA, medical device