Firstly, welcome to the forums.
There is a bit going on here, and several missing pieces… is it possible for you to sketch out a system diagram and post a (cell phone) photo of it?
Im kind of lost about the whole having an R1, not using Ethernet, so having to use an S1.
I am guessing that the JACE is only serial and the R1 does not have any serial modules?
Is the JACE RS232 or 422/485? If its 232, then there is a serial port on the top of the R1 and you could use that and forget the S1… But there may be more to this than my high level guess.
A bigger picture would be really helpful.