Encompass 4 Reader System Guide
vi
RADIO FREQUENCY HEALTH LIMITS FOR ENCOMPASS 4 READER USING AN EXTERNAL
ANTENNA IN FREQUENCY BAND OF 902.25 TO 903.75 AND 910.00 TO 921.50 MHZ
Several agencies (OSHA, FCC, IC) have environmental guidelines regulating maximum
permissible exposure (MPE) or “safe” exposure levels that this product falls under. To ensure
that proper safety guideline for the end users of this product, i.e. Occupational (Controlled) and
General Population/ Public (Uncontrolled), the recommended levels for each of the agencies are
presented in the next sections with TransCore’s recommendations for safety in the last section.
OSHA (Occupational Safety and Health Administration)
OSHA (an agency of The United States of America) legislates in the Code of Federal
Regulations (CFR) Title 29 Part 1910 Subpart G 1910.97 titled “Nonionizing radiation”, a
maximum safe exposure limit of 10 milliwatts per square centimeter (mW/cm
2) during any 0.1-
hour period (i.e. 6 minutes). Using the frequency (in the middle of the band of operation of this
equipment) of 915 MHz and the highest antenna gain that this equipment is certified for use in a
final installation, the minimum safe distance was calculated to be 8in (20cm).
FCC (Federal Communication Commission)
FCC (an agency of The United States of America) legislates in the Code of Federal Regulations
(CFR) Title 47 Chapter I Subchapter A Part 1 Subpart I Section 1.1310 titled “Radiofrequency
radiation exposure limits” that the maximum permissible exposure (MPE) is the following:
Occupational/Controlled Exposure
Power density = frequency(in MHz)/300 mW/cm
2
with an Averaging time of 6 Min
General Population/Uncontrolled Exposure
Power density = frequency(in MHz)/1500 mW/cm
2
with an Averaging time of 30 Min
Using the frequency (in the middle of the band of operation of this equipment) of 915MHz and
the highest antenna gain that this equipment is certified for use in a final installation, the
minimum safe distance was calculated. The MPE minimum distances are 14in (36cm) for the
Occupational/Controlled environment, and 31.5in (80.5cm) for the General Population/
Uncontrolled environment.
Industry Canada (Innovation, Science and Economic Development Canada)
Industry Canada (a Department of the Government of Canada) sets out the requirements in Radio Standards
Specification RSS-102, Issue 5 guidelines, recommending a maximum safe power density in W/m
2. Thus, the
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