This is kinda "voice router", quite smart box which can route traffic between serial telephone lines (it has 4 ports), and has a lot of interesting features - it can take data from the timeslots and mangle it (it can even act as IP firewall, apparently!), you can telnet into it and configure it in nice text windowed environment and so on. Just quite handy.
The problem is that frequently, you have only some reduced features and control level upon the box. The company now sells the machines with unrestricted feature set by default already, but unfortunately you seem to be just out of luck if you already bought it.
So, after a little bit of assembler hacking of the firmware, we got a nice layer around the computation routine ripped from the original firmware. It is tested on Linux but it should work virtually on any 32-bit x86 machine which has printf (for windows, try to substitute printf for _printf). 16-bit code probably won't work because some evil stack issues, but you might try to insert "push cs" in front of the "call" and perhaps you will be lucky.
You will need recent nasm (0.98.36 is known to work), and that's about it :-). See the file header for the rest of instructions regarding how to get it working. Good luck!
Oh, yes. The file is here. It contains parts of the firmware, so you are permitted to download and use it only if you bought the box, thus are legally owning the firmware copy already. The main function is public domain.