Michael Pont wrote:
> Alan,
>
> Hmmm.  Sounds as though this is even more complicated than I had expected.
>
> What I am actually interested in is the port referred to as "LPT1" (or LPT2,
> 3, etc) in a recent PC, and connected to a printer via a Centronics
> interface.  These ports are accessed via three sequential port addresses
> (usually starting at 0x0378 if there is only one port).
>
> Michael.

Want to make things more interesting? Microcomputers (such as those running
OS9 or FLEX) used to have male DB25 for parallel and female for RS232. The
PC drove me nuts when it came out. Cabling was a nightmare (was it going to
be used with a PC or a terminal et.). I've also played with printing machines
which supposedly dated back to ~1948 that used the exact same pinning on a
DB25 as was used for centronics printers but the voltages where like that
of RS232 (+/- 25V DC). Please take the last part with a grain of salt as I
have no idea if the 1948 date was true or not.

--
Linux Home Automation           Neil Cherry             ncherry@comcast.net
http://mywebpages.comcast.net/ncherry/                  (Text only)
http://linuxha.sourceforge.net/                         (SourceForge)
http://hcs.sourceforge.net/                             (HCS II)

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics