--- Bill Studenmund <wrstuden@zembu.com> schrieb:
> On Wed, 24 Jan 2001, Segfault wrote:
> 
> > Hi all,
> > 
> > I'm trying to make a UPS package I found for FreeBSD (which I used to use
> > on a PC) to work on my Mac Quadra 605.
> > 
> > What the program does is monitor and alter the signal level of specific
> > pins of a serial port connected to the UPS.
> > 
> > >From the source, the various ports monitored or changed are RTS, DTR, RNG
> > and other pins (TIOCM_RTS, TIOCM_DTR and TIOCM_RNG respectively).
> > However, I don't know which pins are mapped to which. PCs have pins
> > labeled as RTS, CTS, DSR, DCD, TxD and RxD but Macs have round serial
> > port connectors with pins labeled as HSKo, HSKi, TxD-, RxD-, TxD+, GPi
> > and RxD+ instead.
> 
> I'm a little confused. I'd expect the UPS to be telling you what is going
> on, but RTS and DTR are outputs - i.e. if we're talking about the Mac,
> they are outputs from the mac to the UPS. Which seems backwards.
> 
> Pin mapping will really depend on the cable you're using, so I'll just go
> over which pins NetBSD worries about, and let you deal with your
> cable. :-)
> 
> HSKo == DTR
> HSKi == CTS
> GPi  == DCD
> TxD+ == unused		Note that TxD+/- form a differential pair
> TxD- == TD		which helps get better signals strength
> RxD+ == connect this to ground
> RxD- == RD		RxD+/- are also a differential pair
> 
> > Therefore, I would like to know which pins are mapped to which. For
> > example, if I checked the signal level of the pin "RTS", which pin on my
> > Mac would actually be checked?
> 
> Note: RTS isn't an output on Mac Serial ports.
> 
> Here's where I'm confused. Your software should be DRIVING the levels of
> output pins, not checking them. :-) I'd expect that you'd really look at
> are the inputs.
> 
> Take care,
> 
> Bill

That's a good point... Does it really matter if I'll be setting something on a
input pin or reading on a output pin? I don't think it really matters to this
particular program--since all it's checking and setting are constant signal
levels--would NetBSD complain?

Lucas.

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