There is a Dectalk PC driver at ftp://ftp.leb.net/pub/blinux/dectalk_pc-0.95.tgz that I actually got to work once. However, I've since discovered that it won't compile with a 2.4.X kernel. I had to change one line in the source code to reflect my base address as set by the dip switches on the card because it was not set at factory defaults. It loaded as a kernel module and then you ran a shell script to load the files from your Dectalk installation disk onto the card. In other words, all it did is load the files provided by Digital into the card under Linux and then created a fake serial port at /dev/dtpc0 that you could send text through. It sort of worked with Emacspeak using its Dectalk Express driver, but spat out a lot of errors about unrecognized commands because Emacspeak thought it was talking to a Dectalk express. So, the driver isn't very useful, but it may be worth studying to see how it goes about loading drivers onto the card and how it talks to it.