Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!gem.mps.ohio-state.edu!apple!agate!shelby!portia!ucscb.UCSC.EDU!alexr
From: alexr@ucscb.UCSC.EDU (Alexander M. Rosenberg)
Newsgroups: comp.sys.mac
Subject: Re: Internal modems for the Mac II
Message-ID: <6252@portia.Stanford.EDU>
Date: 31 Oct 89 10:25:51 GMT
References: <1372@orbit.UUCP>
Sender: USENET News System <news@Portia.stanford.edu>
Reply-To: alexr@ucscb.UCSC.EDU (Alexander M. Rosenberg)
Organization: Univ. of California at Santa Cruz Hacker's Anonymous
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In article <1372@orbit.UUCP> pj@pnet51.orb.mn.org (Paul Jacoby) writes:
>Leonard writes (with respect to internal modems):
>>>        I can not comment on the modems themselves (as I have not used all
>of
>them, and some only briefly) but the way they work is since the Macintosh OS
>does not understand more than two serial ports or serial devices they must
>patch the OS to think that when a program is tallking to your modem port it is
>really talking to the internal modem.
><<
>
>Does anyone know how the Mac Portable handles it's internal modem AND it's two
>external serial ports?  Special code?  Partial implementation of the CTB?
>.-----------------------------------------------------------------------------.
>| UUCP: {rosevax, crash, orator}!orbit!pnet51!pj |  Working with idiots keeps |
>| ARPA: crash!orbit!pnet51!pj@nosc.mil           |  my life interesting...    |
>| INET: pj@pnet51.cts.com                        |                            |
>`-----------------------------------------------------------------------------'

What really happens is that one of the three ASIC chips in the portable
handles physical mapping of the internal modem to the printer or modem
port. Through software calls to the Power Manager chip, this switching
can be activated. The software Apple supplies only maps the modem to the
modem port, "to avoid confusing the user". The Communications Toolbox
cannot do much to provide all the ports simulationiously, as it is intended
to do on regular Macs. I won't mention my feelings on this internal modem
implementation chosen for the Portable; it may start up some sort of
Holy War. :-)


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