7 Jun
2014
7 Jun
'14
4:24 p.m.
On Sat, Jun 7, 2014 at 2:08 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Everything I have read (books and web pages) says that RS423 is
single-ended. The Macc had differental data lines. The Mac seems
therefore to be RS422 data lines and RS423 handshake lines.
FWIW, 'Designing Cards nad Drivers for the Macintosh Family' (I may have
slightly mis-rememebred that title) calls them RS422 ports. Which they
also aren't
If you only use the single-ended lines, they meet the RS423 spec. That's
why I claimed that they are RS423 ports (ignoring the two extra lines used
for differential signalling).
If you only use the data lines and not the handshaking lines, they meet the
RS422 spec. It seems reasonable to call them RS422 ports if you're willing
to ignore the handshaking lines, which of course are not required by RS422
(or RS423).
On Fri, Jun 6, 2014 at 3:53 PM, Tony Duell <ard at p850ug1.demon.co.uk>
wrote:
> Was there anythign abotu the early-ish Macs (up to the Mac II series at
> least) that was anything like stanard? The serial ports (both the
> origianl D9s and the 8 pin mini-DIN were not any standard interface
(they
were not
RS422 ro RS423 as far as I can tell).
They were RS423.