HRI-4851L Downlink Documentation

Just reaching out, does any documentation exist for how to structure a downlink for the HRI-4851L?

Looking for what options are available within the downlink ie. can I call a register to be called or polled not in existing list, can i change poll times or add a new register or list to be polled? also what port to send it on as i would like to use this in class c when I am able to get the relevant docs.

Any documentation at all on this?