User Manual

Table Of Contents
FlexNet SmartPoint Radio Overview A-5
SmartPoint Module for the Elster A3 Meter ECMTM40000
A.3.3.1Buddy Mode Using mPass Transmissions
Figure A-1: Remote SmartPoint to Tower mPass Buddy Mode Schematic
Figure A-1shows how a remote SmartPoint device out-of-range of any tower, an ORD, can send
messages in mPass mode to other Buddy transceivers, which then relay the ORD messages on to
the tower.
1. The out-of-range transceiver (or transmit only device) sends an mPass
modulated message which is received by multiple Buddy transceivers. Each
Buddy queues the message to be repeated with a timeout inversely
proportional to the signal-to-noise ratio (SNR) of the message it received, plus
a small pseudo random amount. Closer Buddy transceivers will have a
shorter timeout.
2. The rst Buddy to timeout and repeat the message sends it directly to the
tower on the Normal mode channel. If the tower does not hear the repeated
message, nothing happens until the next Buddy timeout occurs and the next
buddy repeats the message.
3. Once the tower hears a repeated message from a Buddy, it sends an
acknowledge (Ack) message with the ID of the repeated message, which
causes all Buddy devices with a message still queued from that ID to
eliminate that message from their queue. This minimizes the number of times
the message is repeated on air.
A.3.3.2Tower mPass Buddy Mode to ORD Command Transmissions
Figure A-2 exhibits how a remote SmartPoint device that is out-of-range of commands from a
tower can receive those commands via a Buddy relay of the message.