Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!math.lsa.umich.edu!caen!mondo.engin.umich.edu!davids
From: davids@mondo.engin.umich.edu (David Snearline)
Newsgroups: comp.protocols.appletalk
Subject: Wiring constraints for AppleTalk
Keywords: wiring
Message-ID: <1990Aug2.130240.4369@caen.engin.umich.edu>
Date: 2 Aug 90 13:02:40 GMT
Sender: davids@mondo.engin.umich.edu (David Snearline)
Distribution: usa
Organization: Computer Aided Engineering Network, University of Michigan
Lines: 31

In response to gww's (WARD@TECR.NOSC.MIL) message on the wiring specs for
AppleTalk LocalTalk nets:

According to the original Inside AppleTalk, (circa 1985), the mechanical
specifications for "AppleBus" (ie. LocalTalk) cabling are:

		Conductors:	22 AWG stranded 17ohm/300 meters
		Shield:		85% coverage braid
		Impedence:	78 ohm
		Capacitance:	68 pF/m
		Max Length:	300 meters

From experience I know that you can push LocalTalk beyond these specs, but
the closer you get to a full length net (300 m), the closer you will need to
be to the specs.  For an eight node network within our dormitory, a group of
us used shielded 24 AWG audio cable, which ran fine with no data loss.

One little anecdote is that we ran LocalTalk under the carpet for 2 meters
using ribbon cable, since we had to cross the hallway inconspicuously.
We ran two ribbon wires for each LocalTalk wire, and with that the connection
was as good a real LocalTalk. :-)

-------------------------------------------------------------------------------
|   David Snearline                  |   Computer Aided Engineering Network   |
|   davids@mondo.engin.umich.edu     |   University of Michigan Engineering   |
-------------------------------------------------------------------------------
--
-------------------------------------------------------------------------------
|   David Snearline                  |   Computer Aided Engineering Network   |
|   davids@mondo.engin.umich.edu     |   University of Michigan Engineering   |
-------------------------------------------------------------------------------