Re: Apple //c plus serial pinouts?

[dempson@actrix.gen.nz (David Empson)]

In article <2qgb83$qh0@hermes.unt.edu>,
Phillip "Ty" Young <tyoung@jove.acs.unt.edu> wrote:
> Someone told me that these serial port pinouts on the //c plus are the 
> same as on a mac -- true?  If not, how do they differ ?

Basically, yes.  The only differences:

1. The IIc+ doesn't support RS-422, so it doesn't have the TxD+ and
RxD+ signals (pins 6 and 8).  Pin 8 is not connected, pin 6 goes to
the ground signal.

2. The IIc+ doesn't have the "general purpose input" on pin 7.  Nor
does the Mac Plus, but the IIgs and later Macs do have this pin.

3. You cannot feed an external clock signal into the receive flow
control line.

4. The voltage levels are higher (about +/- 12V, instead of +/- 5V).
The only signifcant point about this is that the Mac and IIgs
sometimes have trouble with fussier RS-232 devices which expect higher
voltages.  The IIc+ is more likely to work with these devices.

For standard connections to a printer or modem, you can use the same
cable.  There may be differences with a hardware handshaking cable
(assuming you can use one at all - the IIc+ has the same limitations
here as the IIc).
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand