sda12 is a package of software for working with the B&B Electronics 485SDA12 RS-485 analog and digital data acquisition device.
The software is written in C++ and works on Linux (it probably has some dependencies on ideosyncrasies of Linux RS-232 ports but is probably fairly easy to port anywhere).
The package consists of these parts:
You can download the code from here.
The current release was released in February 2006.
sda12 is distributed and maintained by Bryan Henderson, who is also a daily user of it. (firstname.lastname@example.org).