Xref: utzoo comp.sys.ibm.pc:30583 comp.periphs:1853 comp.misc:6408
Newsgroups: comp.sys.ibm.pc,comp.periphs,comp.misc
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: RS-232 protocol primer (long)
Message-ID: <1989Jun26.155855.1680@utzoo.uucp>
Organization: U of Toronto Zoology
References: <1538@mtunb.ATT.COM> <592@megatek.UUCP> <1989Jun24.005740.19326@cs.rochester.edu> <1954@ssc.UUCP>
Date: Mon, 26 Jun 89 15:58:55 GMT

In article <1954@ssc.UUCP> markz@ssc.UUCP (Mark Zenier) writes:
>"3.1  The interface between the data terminal equipment and the data 
>communications equipment is located at a pluggable connector signal interface
>point between the two equipments.  The female connector shall be associated
>with, but not necessarily physically attached to the data communications 
>equipment..."
>
>Dec and Zenith and very few others get it right, and put a male connector
>on their DTE ports.  Lear Seigler, Qume, and every japanese printer 
>manufacturer I've seen need a sex education lesson.  

Ah, but note the wording in the quoted section carefully.  It says that
the interface occurs at *one* interface point, where the DCE shall have
a female connector.  It says nothing about what's on the other end of the
cable.  In fact, the original rule was that the cable was supposed to come
with the DTE, making sex of connector (if any) at the DTE end unimportant.
Mind you, it still makes sense that *if* you have a connector at the DTE
end, it rationally ought to be male, but this isn't formally required.

Actually, if one wants to be rational about it, equipment ought to have
male RS232 connectors whenever physically possible.  The way these
particular connectors are built, the male connectors are much more
durable (solid post, as opposed to the springy sleeve on the female end),
so they ought to be used in the position where the connector is harder
to replace.  That is, on the equipment rather than the cable.  (If you've
ever wondered why VME backplane connectors are "inverse DIN", with male
on backplane and female on board, that's why.)
-- 
NASA is to spaceflight as the  |     Henry Spencer at U of Toronto Zoology
US government is to freedom.   | uunet!attcan!utzoo!henry henry@zoo.toronto.edu