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- From: heiby@chg.mcd.mot.com (Ron Heiby)
- Subject: RS-232 and DTR when system dies
- Message-ID: <1993Jan6.211938.3214@chg.mcd.mot.com>
- Organization: Motorola Computer Group, Schaumburg, IL
- Date: Wed, 6 Jan 1993 21:19:38 GMT
- Lines: 31
-
- I have been having a philosophical discussion with one of my
- colleagues, on the subject of the DTR line in the RS-232 standard.
- I'm looking for information to help resolve the disagreement that has
- emerged.
-
- My interpretation of RS-232 is that the DTR line should be asserted
- *only* when the DTE is ready to exchange data. My colleague believes
- that that is an over-strict interpretation.
-
- The exact situation in question is what should be done with DTR on
- serial ports coming from a UNIX based computer system that has either
- locked up or panic'd.
-
- In my opinion, this circumstance is such that the DTE (the UNIX
- computer system) is *not* ready to exchange data, so the DTR line
- should not be true. My colleague believes that it is not important
- that the modems attached to the dead computer continue to answer
- incoming calls, and that since previous versions of the system
- software have behaved in exactly the same way for half a dozen years
- or more, that it's no big deal either way.
-
- I'm looking for opinion as to what the *right* thing to do is and how
- important it is to do the *right* thing. I'm also looking for actual
- data regarding computer systems from various vendors, and their
- treatment of DTR in such a situation.
-
- Thanks!
- --
- Ron Heiby, heiby@chg.mcd.mot.com Moderator: comp.newprod
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