3435ras@houxb.UUCP (R.SCHREIBMAIER) (10/14/83)
Sorry for the lateness of this article, but I just started subscribing to this newsgroup. About a week ago there was an article summarizing the responses on cheap 1200 bps modems. One of the comments received said that RS-232 was absolutely clear that DCE are wired with a female DB-25 connector. This is only half correct. The part about a female connector on a DCE is correct. However, believe it or not, even though it gives pin assignments, NOWHERE in RS-232C does it tell you what connector to use! And it hasn't been changed in 14 years! Incredible! A small thing, sir, but mine own. Bob Schreibmaier AT&T Information Systems Lincroft, N.J.
rbc@houxw.UUCP (R.CONNAGHAN) (10/17/83)
If referance to DCE ports having female connectors: I have found the industry to not care if the port is DCE or DTE, the rule of thumb is if its a box make it female and if its a cable make it male. I have read the spec for RS232-C and indead it dosn't even mention the shape or type of connnector let alone the gender. Robert Connaghan Bell Labs, N.J. ...!houxw!rbc
rf@wu1.UUCP (10/17/83)
Bob Schreibmaier is absolutely correct. The connector types are not specified in RS-232. When RS-232 was written all interested parties knew what connectors to use, since RS-232 was an EIA blessing of an AT&T modem standard. RS-232 also does not specify the timing relationships between signals, making the design of networks which take their carrier signals seriously a difficult matter. EIA has promulgated the RS-449 standard as a replacement for RS-232, but no-one is taking it seriously even though it does specify a signalling standard which would guarantee the operability of 200 foot cables. Since a 212 class modem now fits on a rather small card it is now sensible to build your modems into computers and terminals and I expect that RS-232 and RS-449 will slooowly fade away. Randolph Fritz Western Union Telegraph
jhh@ihldt.UUCP (10/19/83)
I remember hearing back in the distant past that HP had some sort of basic patent on RS-232 products, and that you could not manufacture RS-232 products without a license (available for some nominal cost.) Anyone else remember that? John Haller
henry@utzoo.UUCP (Henry Spencer) (10/22/83)
My recollection is that the original Bell standards said that the
modem is supposed to be female, and the thing that connects to it
is supposed to *SUPPLY THE CABLE*, which obviously has to have a
male end to fit the female modem. In other words, technically your
terminal is supposed to come with a cable that plugs into the terminal
(somehow) and presents a male RS232 end to the outside world.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henry