Westermo RM-505U-K - Manual (Page 18)

505K Radio Telemetry Module User Manual
    ELPRO Technologies Pty Ltd 2008 Page 18
consumption is considerably increased. These periods should be minimised if you are using a
battery pack.
2.7 Security Considerations
There are a couple of dimensions of security considerations:
• Failure to operate when required - or “operational reliability”.
The 105U modules use an acknowledgment and re-try protocol to ensure that the transmitting
module is aware whether the transmitted message has been transmitted reliably. The 505K
module is not able to do this, and hence does not have the same level of reliability. However
the ability to transmit each message multiple times does improve the reliability. A “fail to
receive” alarm at the receiver provide indication if the radio link has failed to operate.
• Malicious operation, or “hacking”
This is the problem most associated with security concerns - the ability for someone to
access information from a radio system by “listening-in”, or to cause damage by transmitting
radio messages to force outputs.
A security option can be selected during the module configuration to protect against this. The
security option (if selected) adds data encryption to radio messages. Modules in the same
system are automatically configured with the encryption key, such that only these modules
can understand each other. “Foreign” modules will hear the messages, but cannot decrypt the
messages. For more information, refer to section 4.3.7 of the 105U I/O User Manual.