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From: roy@phri.UUCP (Roy Smith)
Newsgroups: net.periphs
Subject: RS-232 vs. The Apple LaserWriter
Message-ID: <2457@phri.UUCP>
Date: Mon, 20-Oct-86 17:15:22 EDT
Article-I.D.: phri.2457
Posted: Mon Oct 20 17:15:22 1986
Date-Received: Wed, 22-Oct-86 04:33:45 EDT
Reply-To: roy@phri.UUCP (Roy Smith)
Organization: Public Health Research Inst. (NY, NY)
Lines: 22
Keywords: DTE, DCE, RS-232


	I just got my 2nd Apple LaserWriter and noticed that they have
re-written the manual a bit since I bought my first one 6 months ago.  In
particular, they go into a bit more detail when they talk about the comm
connectors.  Quoting from Appendix C, page 124:

	Technically, the LaserWriter has a "DTE" type of RS-232
	interface.  This means it can be connected directly to a
	host computer or a modem, with no signal reversals required.
	Connecting to a terminal requires interposing a modem
	eleminator [sic] (null modem) cable ...

	Now, I don't claim to be an expert on RS-232 (although I usually do
manage to get things to work), but isn't that wrong?  Shouldn't a "host
computer" also be a DTE?  My Sun-3/50 has DTE ports on the back, and the
various serial ports on my Vax are also DTE.  Is it common practice in
personal computers (whose owners, I assume, are the intended audience of
this manual) to have comm ports wired DCE?
-- 
Roy Smith, {allegra,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016