Intercom was originally written in C code for inclusion in C programs. For C programmers this was quite acceptable. Unfortunately the vast majority of non-professional programmers do not work in C, so something needed to be done.

I've taken the original C code and placed it into a plain C DLL. Most higher level languages like Visual Basic and Delphi can utilize the subroutines in a C DLL. Since I'm a professional Visual Basic programmer I'll be using VB as my language of choice in the following examples.

First, what is intercom? Intercom is code that creates a memory-mapped file that both CC2 and your program can use. What this means is that in memory a chuck of space is set aside, half for you and half for CC2. You can only read your half and you can only write to CC2's half. CC2 on the other hand can do just the opposite.

Whenever a new message is written, a 'New mail flag' is raised. CC2 looks for a raised flag automatically. Your VB program needs to check periodically.

Second, what is it that is sent back and forth between CC2 and my program? Intercom sends an integer and a string back and forth. To CC2 these have very strict meanings. The integer is part of the name of the macro it will now run and the string is used as input data.

If you sent CC2 via intercom the number 123 then the macro CC2 will attempt to run in named RCV123 and the string will now reside inside the variable RCVDATA.