ANT Forum

Dear all,

I hope you can help me with this simple question:

If my ANT master device (bidirectional tx channel) receives acknowledged data from different slaves (bidirectional rx channel), how can I know the emitter of that data (I mean the device number of the slave emitter)?

Thanks in advance,
DW      

If a master sends an acknowledge message to multiple slaves (all on the same channel), they will all ack back simultaneously and the transmissions may collide. It is not possible for the master to tell them apart, and for that reason it is not recommended to use acknowledged messages in the forward direction when connecting to multiple slaves.

A shared channel does allow sending ack messages to multiple slaves on the same channel, as they will only send the ack back when addressed directly (i.e, the master would need to send a message to each sequentially).      

Well, I didn't mean that the master will send an acknowledge message (sorry for bad my english), but the slave instead. I will try to explain it better:

Imaging that the master is sending periodic broadcast messages to all slaves.
Suddenly, one of the slaves answers with an acknowledge message.
From the master point view, how can it knows the device number of the slave who answered?

I am asking that because I want to avoid identifying the slaves in the payload bytes (of the acknowledge message).

Thanks again      

It is not possible to differentiate - the channel ID in the messages sent from the slave is the same as the one from the master. You will need to use a portion of the payload to identify the slaves.

Depending on your application, you may want to have a look at shared channels.