Re: Is it possible to receive data on a //c's printer port?

[David Schmenk <dschmenk@gmail.com>]

On Thursday, 13 June 2013 20:07:57 UTC-7, Ivan X  wrote:
> On Monday, June 3, 2013 5:44:41 PM UTC-4, Moose wrote:
> 
> > Yes, the printer port is definitely bi-directional.
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> > 
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> > My Apple //c printer cable is also a null-modem cable - so I can plug the end into a PC with a serial port and start transferring disks with ADTPro.  I don't know / can't remember if this was the case for all / most //c printer cables.
> 
> 
> 
> Well, this is definitely not the case on my platinum keyboard //c (ROM version 3), or my IIc Plus (ROM version 5). The same cables which work fine with ADTPro on the modem port do not work when plugged into the printer port. It says WAITING FOR HOST REPLY and never starts; on the server side, it says "No Activity". I've tried various baud rates, no go. But it all works fine on the modem port, though.
> 
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> And, I do find the fact that IN#1 is non-operational -- entirely and visibly by design -- to be very suspicious. (To reiterate, IN#1 on my machines returns four developer names in a string -- which results in a ?SYNTAX ERROR if you haven't written a program to catch it -- and does NOT go into any kind of interactive mode like IN#2 does, or IN#1 on my IIgs does. CTRL-A and CTRL-I do nothing, and I can't "type" over the serial port.)
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> I think that the printer port on the later (platinum keyboard) //c's might be outbound-only.

IvanX- maybe the other DaveX will chime in, but I believe ADTPro only works with the modem port on the //c.  There is no way to select multiple serial cards in ADTPro, so I'm guessing it uses first one it finds when scanning down from slot 7.  Aside from some differences in interrupt connections and firmware, the 6551's are wired the same.  You can check out how the interrupts may affect how the serial ports operate by looking at the //c tech ref man.

Dave...