The Unitelway protocol used on serial links allows communication between a master device and one or more slaves.
The dialogue is always initiated by the master and no slave can decide to speak without the master having given it to him.
The master thus cyclically interrogates each slave in order to assign them a speaking time.
If the slave does not respond to this type of request, the master passes the floor to the next slave after a timeout.
If the communication is via an ARM radio link, the timeout must be increased on the master side due to the transmission delays of the radio modems.
For safety reasons, it is recommended to set this parameter to 100ms.