Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!mailrus!uflorida!gatech!cadeta!galbp!wittsend.LBP.HARRIS.COM!mhw
From: mhw@wittsend.LBP.HARRIS.COM (Michael H. Warfield)
Newsgroups: comp.dcom.modems
Subject: Re: Break definition
Message-ID: <6118@galbp.LBP.HARRIS.COM>
Date: 13 Sep 88 15:13:06 GMT
References: <402@ucrmath.UUCP> <6095@galbp.LBP.HARRIS.COM> <569@pcrat.UUCP>
Sender: news@galbp.LBP.HARRIS.COM
Reply-To: mhw@wittsend.UUCP (Michael H. Warfield)
Distribution: na
Organization: Harris/Lanier Network Knitting Circle
Lines: 30

In article <569@pcrat.UUCP> rick@pcrat.UUCP (Rick Richardson) writes:
>In article <6095@galbp.LBP.HARRIS.COM> mhw@wittsend.UUCP (Michael H. Warfield) writes:
>>        A break is sent on an async line by placing the  line  in
>>the  "low" or "spacing" state (level, tone, what-ever) for two or
>>more charracter times.  To a receiver this would  be  seen  as  a
>>charracter  of  all zeros, with a framing error (no stop bit) and
>>lasting at least 20 bit times (16 data bits  plus  2  start  bits
>>plus  two  stop  bits total across the 2 charracter times).  Note
>>that that is AT LEAST.  Some UARTS support long and short  breaks
>
>Where did you find the citation that a break is at least 20 bit times?
>The only citation I could find (in some obscure CCITT spec) defined
>break as the space condition for at least 130 milliseconds.  There
>was no formula based on the bps that the interface was operating at.
>
        Point taken.  The information I was quoting was based  on
several  USART  chip  specs (I know, I know, bad move) and not on
any particular specification.  At this  point  I  have  seen  the
references in the chip specs, as well as other feed-back from the
net specifing anything from 100 msec on  up  (250  msec  seems  a
common  opinion).   I would also like to see some hard fast specs
on this as well.  None of my comms  references  mention  specific
timings and I have little to go on outside of the specs I have on
hand ( Yeah, I  guess  when  it  comes  to  manufacture's  specs,
there's   a  sucker  born  every  minute  ;-) ).

Michael H. Warfield  (The Mad Wizard)	| gatech.edu!galbp!wittsend!mhw
  (404)  270-2170 / 270-2098		| mhw@wittsend.LBP.HARRIS.COM
An optimist believes we live in the best of all possible worlds.
A pessimist is sure of it!