12 Sep
2002
12 Sep
'02
8:51 a.m.
On Sep 12, 9:51, Ethan Dicks wrote:
That won't work. The LocalTalk/PhoneNet adapters are not passthrus.
Apple LocalTalk adapters contain self-terminating connectors (the
plastic pip in the end of the cable pushes on a switch that disengages
the internal terminator; PhoneNet adapters use RJ-11s with
external terminators), and both adapters contain at least a transformer,
IIRC to couple the Mac to the network. There might also be a resistor
or two in the adapter. I haven't opened up one in over 10 years.
All the commercial LocalTalk and Phonenet adaptors contain an isolating
transformer, which is carefully designed to preserve nice clean square
waves from one side of the interface to the other. Note that you can't
just use any old small transformer! There's a web page describing the
innards at
http://ground.ecn.uiowa.edu/apple2/MiscInfo/Hardware/appletalk.phonenet
It's also commonly believed that the Farallon Phonenet system using
unsheilded cable works better than Apple's own grounded shielded cable
system.
However, I have seen one DIY design that didn't use an isolating
transformer. Called CapNet, it was intended for small networks, and used
capacitors to acheive some degree of isolation. A slightly updated version
was claimed to work with printers and the like.
http://hyperarchive.lcs.mit.edu/HyperArchive/Abstracts/info/hdwr/at-connectā¦
http://www.loten-am-mac.yucom.be/cap1.htm
--
Pete Peter Turnbull
Network Manager
University of York
--- Carlos Murillo <carlos_murillo(a)epm.net.co>
wrote:
> >> Now I have another question: How do you
connect the Fastpath 4's
> >> DE-9 Localtalk connector to a phonenet network?
With a standard (ancient) DE-9<->PhoneNet
adapter. Barring that, I
have made DIN-8 to DE-9 LocalTalk adapters
You would need a female DIN-8 connector to go the
other way.
That would be the trickiest part... I think that I should
try wiring the DE9 directly to a 4wire phone cable; it is easier
to find a phone cable than a female DIN8.