We have an existing request in our system to "Implement Opto Serial Transport protocol (OST)," which I believe is what you seek. It requests:
"... PPP without requiring the use of AT commands (dial-up modems). The real issue is that sometimes it is necessary to be able to communicate from an S1 controller to another S1 or to Ethernet brains via a serial connection... Customers have typically tried to implement this via PPP only to find out that PPP requires the use of dial-up modems. In the PAC Family, this would apply to the S-series and R-series. The EB-series could not be included because EB brains do not have a serial port."
Sound like your situation? Odds of this getting bumped up on the priority list will go up, of course, if you (and others) will tell me how many gazillion S1s you'll buy if only we'd implement this.
But perhaps there's another way to solve this problem? What are you connecting this R1 to, the PC running PAC Project, I'm guessing?