Kevin Timmerman sent me email about having built a USB version of the closed-caption decoder that Richard Ottosen and I developed. He used an FTDI TTL-232R cable which incorporates a USB-to-serial interface chip. He has added many new features to the firmware, including ANSI cursor addressing, XDS, and V-chip support, and also has fixed some bugs.
Photos and the source code to his enhanced version are available from his web site.