Wow!  Anne and Jim, thanks for such comprehensive replies.

The spirit of helpfulness on this list is wonderful.  Especially
impressive is your patience with PIC newbies like me.

Magic.  Thanks very much, folks.

Steve Thackery
Suffolk, England.
Web Site: http://www.btinternet.com/~stevethack/

"Having children is hereditary. If your parents didn't have any, neither
will you."    - Henry Morgan