RComm.dll provides for communications between the Nav and Control software and the Lisp software. It uses shared memory within the dll to transfer data messages from the microcontroller and the nav and control software to Lisp, and to transfer command messages from Lisp to Nav and Control.
How it works
Each using application has a copy of the same data structure for each message to be transferred. One application can send the message to shared memory in the dll with a function call. The receiving function can read the message with another function call. See MComm and LComm in the following source code for examples.
Put RComm.dll in C:\Windows\System32 or in SysWOW64 for 64 bit versions of windows. This will make it available to using applications regardless of where they are located. Avoid putting copies of RComm.dll anywhere else where the using applications might find them, this can result in two applications using different copies of the dll and hence not actually transferring data. Especially, don't put a copy in the same folder with one of the applications.