Path: utzoo!attcan!uunet!zephyr!tektronix!psueea!parsely!bucket!leonard
From: leonard@bucket.UUCP (Leonard Erickson)
Newsgroups: comp.sys.ibm.pc
Subject: Re: RS-232 protocol primer (long)
Message-ID: <1513@bucket.UUCP>
Date: 29 Jun 89 06:28:45 GMT
References: <589@megatek.UUCP> <45900244@uxe.cso.uiuc.edu>
Reply-To: leonard@bucket.UUCP (Leonard Erickson)
Organization: Rick's Home Grown Unix; Portland, OR
Lines: 37

In article <45900244@uxe.cso.uiuc.edu> mcdonald@uxe.cso.uiuc.edu writes:
<What's a DCE or a DTE? I never use those words. To be a useful standard,
<it should specify the sex of the connector for each particular type
<of equipment, by its common name:
<1. Computers  -  odd, it never seems to mention computers!!!!
<
<2. Terminals  - Presumably computers and terminals should be the same
<    sex.
<
<3. Printers
<
<4. Modems
<
<5. Scanners
<
<6. Data collection equipment (voltmeters, etc.) - presumably the same as 
<   scanners
<
<7. whatever else people can think of
<
<And, of course, the question of the function of pins 2 and 3 has to be
<worked out!!!

DCE = Data Communication Equipment (ie modems)
DTE = Data Terminal Equipment (ie terminals & computers)

The function of pins 2&3 is determined by whether an item is DTE or DCE.
Printers, scanners, etc are not covered. The standard was intended only
for connections between terminals anmd modems or modems and computers.
Anything else is a use that has been more or less kludged onto a
convenient standard that was never intended to handle it.

-- 
Leonard Erickson		...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I'm all in favor of keeping dangerous weapons out of the hands of fools.
Let's start with typewriters." -- Solomon Short