Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!apple!sun-barr!rutgers!okstate!minich
From: minich@a.cs.okstate.edu (MINICH ROBERT JOHN)
Newsgroups: comp.sys.mac
Subject: Re: Apple Extended Keyboard Pr
Message-ID: <5384@okstate.UUCP>
Date: 16 Feb 90 06:03:36 GMT
References: <8324@wpi.wpi.edu>
Organization: Oklahoma State Univ., Stillwater
Lines: 42

[multiple levels of previous stuff you need not read again about unplugging
 ADB devices while machine is on]
Tim Butler writes...
> I don't think lining things up is the problem. The connecting is to a bus
> that has addresses. If you plug something in while it is on, it is
> supposedly going to have addressing problems. It would seem that just
> sticking it back in after it fell out wouldn't cause a problem, but
> rebooting doesn't take that long.
> 				
> 				-Tim
> 
> (I am by no means a hardware expert, I am just remembering what I've read)
> Tim Butler		(tbutler@wpi.wpi.edu)
> Worcester Polytechnic Institute

  When an ADB device (keyboard/mouse/?) is unplugged, the Mac will soon find
it missing. It polls all the ADB devices many times every second. When you
put a new device on the bus, it should have the effect of resetting the entire
bus. (Although I'm not sure wether the Mac or the device is responisble for 
that part.) Anyways, the real problem with lots of unplug/replug cycles is 
the chance of static buildup zapping a chip. (Worse case, the chip on the
motherboard, which is a board swap at the dealer. :-( ) Someone mentioned this
before, but I think it bears repetition: The original keyboard cabling
scheme was VERY good. Ma Bell isn't too stupid. Phone style connectors are
really great things, an example of practical engineering. Maybe Apple could
change the connectors for ADB to phone style ones. And for that matter, also
LocalTalk cables. The choice of cabling for the Mac (SE and up) is ironic:
the cables on the back that are almost never jostled the slightest bit are
screwed on tightly while the cables that get tugged, yanked, and otherwise
abused on a regular basis just pop out. 
  Does anyone at Apple (or anywhere else) now FOR SURE why the current
connectors were chosen? Just curious.

Robert Minich
minich@a.cs.okstate.edu
Oklahoma State University  "Where the faculty in favor of canning our 
                            give-a-football-player-a-diploma-'cause-he-
                            works-real-hard-even-tho-he's-not-making-
                            minimum-standards President"

I disclaim nothing because if the officialdom can get away with BS, 
this should hardly even be noticied.