IIUC ANT is the basic protocol that allows for a wide range of network possibilities, while ANT+ is a restriction on that which makes for easier interoperability by requiring each device to implement a "profile".

But the basic setup is for the sensors to operate as masters (that transmit) and the head unit/ computer to operate as a slave (that receive). I guess there could be bi-directional comms using ack messages for example but I don't know if that is required in any of the profiles. The sensor has to be placed into "pairing" mode by eg a button push which causes the sensor to transmit an ID. My Garmin slave also needs to be placed into "search" mode which I guess is a receive mode that looks for the pairing transmissions. Once the slave accepts the pairing info it should remain paired. At that point the slave should be listening and when a master (sensor) xmits it should save data if it is paired or ignore it otherwise. At least on my Garmin head unit, it seems to recognize a paired speed/cadence sensor as soon as the magnets pass, so I assume on a single xmit message from the sensor. I haven't checked range, but at least a couple of meters I get reception. The Garmin also shows the saved ID of the paired sensor in the status pages.

scott s.
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