Something a little more contemporary (1985), and rather local to me (the author is an academic in the Computer Lab): http://www.americanradiohistory.com/Archive-Wireless-World/80s/Wireless-World-1985-09.pdf -- page 37 http://www.americanradiohistory.com/Archive-Wireless-World/80s/Wireless-World-1985-10.pdf -- page 73 Neil -- http://www.njohnson.co.uk