Re: LZ: RS-232 & RS-422 Standards
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Re: LZ: RS-232 & RS-422 Standards
On Wed, 2 Oct 1996, A.K.A. TheWiz wrote:
> > The primary problem has nothing to do with the protocol or the number of
> > pins, and everything to do with the way the Mac handles hardware access.
> > (i.e. it doesn't let you control the logic levels of the individual port
> > lines unless you hack the hardware directly (which virtually assures you
> > that it won't work on any other model of Mac).)
>
> True; thus you need some sort of adapter tacked on to adapt the
> voltages (I assume that's what you meant; I don't really know much about
> this sort of thing - yet).
No. What I meant is that the Mac OS and serial hardware handle the ports,
meaning that applications cannot manipulate the individual lines on the
port directly. The only link cable that is capable of turning RS-232 into
TI protocol is the TI GRAPH-LINK. Homebuilt links rely on the ability to
manipulate the signalling lines of the serial port directly. Macs do not
allow this (to my knowledge). This does not matter for standard RS-232
equipment, but it makes it impossible to use unsophisticated hacks like
the "$4" serial port link.
-Isaac
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Isaac Salpeter
the ticalc.org project
isaac@ticalc.org
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