Geoff,
Yes, that is a correct interpretation of the C/MRI protocol. The C/MRI protocol does not have any message formats which deal with only one output, or only one input. It only has formats which deal with "all inputs on the node" or "all outputs on the node".
So, when the "master" changes an output, _all_ outputs on the "node" are written by the master. (It is incumbent on the "master" to keep track of all output values, and modify only the one being targeted; the "master" then updates the node with all of the output values appropriate for that node.)
And, when the "master" queries a node, the node presents values from _all_ inputs on the "node" for the master to "read".
Regards,
Billybob
