Path: utzoo!mnetor!uunet!husc6!linus!gatech!mcnc!ecsvax!ranger
From: ranger@ecsvax.UUCP (Rick Fincher)
Newsgroups: comp.sys.apple
Subject: Re: Synchronous (HDLC) GS?
Message-ID: <4353@ecsvax.UUCP>
Date: 22 Dec 87 22:19:46 GMT
References: <8712181616.AA20668@mitre.arpa>
Organization: UNC Educational Computing Service
Lines: 19
Summary: 8530 can't do SDLC[C[D[D[D[D[DHDLC...

In article <8712181616.AA20668@mitre.arpa>, mcgurrin@MITRE.ARPA writes:
> In browsing through the IIGS hardware and firmware technical manuals, I noticed
> that the serial port uses a multi-protocol chip that supports synchronous
> as well as asynchronous communications.  Does anyone know if this means one
> could use the serial port as a synchronous port, assuming the appropriate 
> driver software was written, or is there no way to access the necessary
> control lines, etc.?  I assume that if possible it would require directly
> accessing the chip, not using firmware.  I would be particularly curious
> if HDLC LAPB could be supported with the appropriate software (a IIGS with
> X.25? an interesting concept!).

The Zilog 8530 SCC chip is the same as that used in the Mac.  The synchronous
mode is used with Appletalk but no one has used it for IBM style synchronous
communications.  If it could be donm[De [D, someone would have done it on the Mac by
now, Iwould think.  You still need an IRMA board for the Mac or some other
such device to do it.  These are available for the Apple II, have been for 
years, but are very expensive.

Rick