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From: resnick@cogsci.uiuc.edu (Pete Resnick)
Subject: Re: Appletalk Interface Card on Ethernet?
Message-ID: <1991Apr9.234119.28385@ux1.cso.uiuc.edu>
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Organization: University of Illinois at Urbana
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Date: Tue, 9 Apr 1991 23:41:19 GMT
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willdm@unix.cis.pitt.edu (William D Moore) writes:

>an HP LaserJet III with a PostScript cartridge, 2 MB of memory, and an 
>Etherprint box on this network, too.  Yesterday I received a copy of the
>order, made by our adminstrators, for a PostScript cartridge, memory, and
>an AppleTalk Interface card.
>   ^^^^^^^^^^^^^^^^^^^^^^^^
>My question is if I'm going to have three macs running on ethernet, do I still
>need an Appletalk Interface card for the LaserJet?  Since the LaserJet and the
>SE's will be communicating via ethernet, Appletalk protocols will not be 
>involved at all, right?

Layers, layers, layers. Let's all get this straight. Ethernet is a low-level
protocol that happens to run over a certain kind of hardware, confusingly
referred to as Ethernet. Appletalk is a higher level protocol that takes
care of its own low-level protocol when it is run over LocalTalk, but gets
wrapped in the Ethernet protocol when it is running on Ethernet hardware.
Any printing you do from your Macs is most certainly going to be in
Appletalk protocol, just wrapped in Ethernet for its low-level transport.
Now, Etherprint boxes only convert from Appletalk-on-Ethernet to Appletalk-
on-LocalTalk. So your HP, which comes from the factory with only a serial
and/or parallel port, better learn to speak Appletalk to talk to the
Etherprint box, and connect to the LocalTalk port on it, hence your card.

pr
--
Pete Resnick             (...so what is a mojo, and why would one be rising?)
Graduate assistant - Philosophy Department, Gregory Hall, UIUC
System manager - Cognitive Science Group, Beckman Institute, UIUC
Internet/ARPAnet/EDUnet  : resnick@cogsci.uiuc.edu
BITNET (if no other way) : FREE0285@UIUCVMD