User's Manual

Table Of Contents
Health Limits for Encompass
®
Multiprotocol Reader
Using External Antenna (902 to 921.5 MHz)
Within the United States, environmental guidelines regulating safe exposure levels are issued by the Occu-
pational Safety and Health Administration (OSHA).
Section 1910.97 of OSHA Safety and Health Standards 2206 legislates a maximum safe exposure limit of
10 milliwatts per square centimeter (mW/cm
2
) averaged over 6 minutes at 902 MHz.
Although not binding, other organizations such as the American National Standards Institute (ANSI) have
issued similar guidelines that are more restrictive than the OSHA limits (ANSI C95.1). ANSI guidelines
recommend a maximum safe power density in mW/cm
2
of:
Frequency
(in MHz)
1500
Thus, the maximum permissible exposure for general population/uncontrolled exposure at 902 MHz is
0.60 mW/cm
2
. The average time is thirty minutes.
The maximum permissible exposure for occupational/controlled exposures is 3.0 mW/cm
2
. The average
time is six minutes.
The RF power density generated by the Encompass Multiprotocol Reader was calculated using a maxi-
mum antenna gain of 14.0 dBi, equivalent to the antenna gain of the external AA3152 Universal Toll
Antenna (UTA).
Warning
At 2 W transmitted power, 0 dB transmit attenuation, and a distance of 33 inches (82 cm) from the
antenna, the maximum power density calculated was less than 0.60 mW/cm
2
. Install the antenna at least
33 inches (82 cm) from the general public. Maintenance personnel must remain at least 15 inches
(37 cm) from the antenna when the system is operating.
The data confirms that when the UTA, or equivalent antenna, is used with the TransCore Encompass
Multiprotocol Reader, the antenna effectively meets OSHA requirements and thus does not represent an
operating hazard to either the general public or maintenance personnel.
PRELIMINARY