Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!apple!sun-barr!newstop!sun!concertina!fiddler From: fiddler%concertina@Sun.COM (Steve Hix) Newsgroups: comp.sys.apple Subject: Re: Obsolete //c ? Message-ID: <126256@sun.Eng.Sun.COM> Date: 12 Oct 89 23:16:31 GMT References: <8910071353.aa04204@ADM.BRL.MIL> Sender: news@sun.Eng.Sun.COM Lines: 31 In article <8910071353.aa04204@ADM.BRL.MIL>, SEWALL@UCONNVM.BITNET (Murph Sewall) writes: > On Thu, 5 Oct 89 18:32:02 GMT you said: > >I seem to remember the 1200 baud problem occured only in the 1st year > >of production of //c's and was only a problem with 8 bit transfers (such > >as would occur in XMODEM) and not with regular ASCII (7 bit) terminal > >emulation. > > Your memory is faulty. I have seen the problem up close and personal. > It's a timing problem and it doesn't matter if the incoming characters are > a file transfer packet or an ordinary line of text to be displayed on the > screen. If that's the problem, it effects everything. The problem was caused by a sometimes slightly out-of-spec crystal on the //c motherboard. Sometimes you were lucky, sometimes you got a bad one. The fix (a better quality crystal) gave an excuse to upgrade the firmware at the same time. (Kudos to Rich...) I was in the middle of this, getting to rev the //c technical reference manual documenting the new ROM and stuff. Some modems were pretty tolerant of the problem, others, mostly non-Apple were not. The fix was worth it just for the MouseText characters it gave you. ------------ "...I was to learn later in life that we tend to meet any new situation by reorganizing: and a wonderful method it can be for creating the illusion of progress, while producing confusion, inefficiency and demoralization." - Petronius Arbiter, 210 B.C.