User's Manual

Introduction – Radio performance 3
RIM 902M OEM Radio Modem – Integrator’s Guide
Low power requirements
If you are planning to integrate the RIM 902M into a handheld or portable
device, battery life is a critical issue: your customers will insist on long lasting
devices without heavy battery packs. The RIM 902M sets a new power
consumption standard for Mobitex radio modems. This ensures efficiency and
maximizes battery life.
Transmitting data: 1.7 amps or less (at 4.5V), depending on output power
The transmitter is ON for a pulse of between 32 ms and 1 second per
packet, depending on the amount of data transmitted. The maximum
packet size for a Mobitex device is 512 bytes.
Receiving data: 60 mA (at 4.5V)
The radio turns its receiver ON for a 150 ms “window” once every 10
seconds. The base station will only attempt to communicate with the radio
during this window. To minimize latency during rapid two-way
communication, the receiver is also turned ON and kept ON for 10
seconds after any communication (transmit or receive) with the network.
Standby power: 0.3 mA (at 4.5V)
Standby power consumption is very low and occurs when no radio activity
has taken place for at least 10 seconds. The radio and base station are
closely synchronized to ensure that a communication attempt is not missed
when the radio is in standby mode.
Battery life is not a concern for certain applications, such as in-vehicle
applications that draw power from the vehicle battery. For these applications, it
is possible to put the radio in an express operating mode, in which power
consumption is higher than normal but packet transfer latency is reduced to a
minimum.
Small size
Using a single board design, the RIM 902M is very thin, and much smaller
than a business card, at only 42.0 by 67.5 mm. This tiny size allows the
RIM 902M to meet tight space requirements within most applications. The fact
that a single board is used means that the device is much more reliable than
multi-board designs, particularly in high-vibration environments such as
vehicles.