Integration Guide

SATEL-TR4+
Integration Guide, Version 1.7
31
9.2 Electrostatic discharge
As the module is intended to be embedded in a host application, in a typical use case, the antenna
port is the only port of the module directly interface with a surface or contact area subjected to
Electrostatic Discharge (ESD). Thus, the antenna port is the only interface with high level ESD
protection. The DTE port also features ESD protection diodes, but is not designed to withstand
similar performance as expected from standalone units with enclosures.
Consequently, the module should be subject to ESD handling precautions that typically apply to
ESD sensitive components. Proper ESD handling and packaging procedures must be applied
throughout the processing, handling and operation of any application that incorporates this
module.
9.3 Using the device in unmanned high reliability applications
The module features software and hardware watchdogs which are incorporated inside the CPU.
While we believe that this is a reliable method of keeping the module in operational condition,
there are parts of the module that can’t be monitored for proper operation to 100%. For example
the module chip has a firmware that resides in the chips RAM. The firmware can’t be read back or
reloaded, without interrupting reception. Hence the module can’t reload this automatically by
itself without causing breaks in communication. To avoid the module from ending up in a state
where for example the module chip firmware is corrupted for example by ionizing radiation, it is
recommended that the controlling system implements some form of watchdog function for the
module. This can be done for example if the system knows that data should be received every
second, and no data has been received for a minute – then do a module restart using the
ENA_MOD pin or by issuing a restart command, or a cold boot by toggling VCC_IN low and high
again.
9.4 PROPOSALS FOR MORE RELIABLE RADIO LINK
In case where the environment is challenging the following methods can be used for improving
the transmission reliability:
• Forward Error Correction, FEC, is recommend to use in challenging environment like
urban areas.
• Directional antennas.
• Before building the radio link(s) it is highly recommend that the radio environment is
measured to find out whether the radio environment is clean enough by using a
spectrum analyzer or radio module’s RSSI, Received Signal Strength Indication, value.
• Co-operation with the local authority to find out the optimum free radio channel.