Maximum Number of RDM Enabled DMX Splitters on an RDM Link
The maximum number of RDM enabled opto-splitters that may be daisy chained together is 4. Since RDM splitters have to shorten the time between some of the packets, chaining more opto-splitters will result in unsatisfactory performance.
It's also important to remember that legacy DMX opto-isolators are typically uni-directional. Put simply -- if the DMX opto isn't labeled with the word RDM, it probably isn't capable of taking in data from the DMX outputs and sending it back to the DMX input.