It's a "dummy centronics" driver that opens a linux named pipe and sends it directly to the ap2000 driver. In the code it's "/dev/lp0" but you could change that to any filename and just mkfifo. When I was fiddling with it, I changed it to a "lp0" filename in my directory.
It's really slick in that you can send it data from any linux application, like doing stuff from the command line: echo "hello" > /dev/lp0
+ const char *fname = "/dev/lp0";
+ m_pipe = open(fname, O_RDONLY | O_NONBLOCK);
+ m_keepalive = open(fname, O_WRONLY | O_NONBLOCK);
+ m_fp = fdopen(m_pipe, "r");