RIM 902M, Integrator Manual

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Introduction – FCC radio frequency exposure rules 5
RIM 902M OEM Radio Modem – Integrator’s Guide
forwards it to the mobile. This prevents data loss, and increases the reliability
of transmission.
Mobitex is optimized for data communication. It uses a packet switching
technique to provide the greatest flexibility in data transmission. Conventional
cellular phone systems, by contrast, use a circuit-switched network, in which a
physical connection is created between the sending and receiving nodes, and
must be maintained throughout the duration of the transmission. With circuit-
switched systems, the set-up time for establishing a connection involves
significant overhead and airtime cost, especially when only a small amount of
data needs to be transferred.
Mobitex packets include information about the origin, destination, size, type,
and sequence of data to be sent. This enables packets to be transmitted
individually, in any order, as traffic permits. Internal to the network, individual
packets may travel along different routes, in any order, without interfering with
other packets sent over the same frequency by different users. At the receiving
end, all packets are accounted for, and reassembled into the original message.
Set up time is eliminated and network connection is instantaneous. As a result,
packet-switching makes far more efficient use of channel capacity, typically
allowing 10 to 50 times more users over a radio channel than a circuit switched
network.
FCC radio frequency exposure rules
Based on FCC rules 2.1091 and 2.1093
(1)
and FCC Guidelines for Human
Exposure to Radio Frequency Electromagnetic Fields, OET Bulletin 65 and its
Supplement C
(2)
, all integrations of the RIM 902M OEM unit are subject to
routine environmental evaluation for RF exposure prior to equipment
authorization or use.
For portable devices, defined in accordance with FCC rules as a transmitting
device designed to be used within 20 cm of the user body under normal
operating conditions, RF evaluation must be based on Specific Absorption Rate
(SAR) limits in Watts/kg. SAR is a measurement of the rate of energy
absorption per unit mass of body tissue.
For mobile devices, defined as a transmitting device designed to be generally
used such that a separation distance of at least 20 cm is maintained between the