daemon@ucbvax.UUCP (10/14/83)
From GEOFF5@SRI-CSL Fri Oct 14 03:59:22 1983
A few days ago, I asked if there was a way for a user program on the
VAX under VMS to cause a DZ-11 to transmit a line BREAK. The
concensus of opinion is that although you can't really do it, you can
fake it by changing the line speed temporarily to something very low
and sending a character. Here are the responses I got (slightly
edited). Thanks much. Ron <Heiby @ HI-Multics>.
From: clark.wbst@PARC-MAXC.ARPA
Idea... set the baud rate to less than 1/10th the receiving baud rate
of the called modem, and each bit will be a break... you just send a character
of all 1's - the start bit will cause a single break. You don't want to send
any character because you will get tons of breaks. I have never done this.
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From: Eric P. Scott <EPS at JPL-VAX>
I wish, I wish, I wish. There have been several SIRs about this
and I intend to question Rick Spitz on this matter at LV DECUS.
Before Unix provided this capability the trick was to temporarily
set the line speed to 150 baud and send a particular string that
would cause a framing error on the other side.
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From: Stephen Tihor <TIHOR.CMCL1@NYU.ARPA>
The solution we used in our unpriveledged software (can't get to the funny
hardware bits, doesn't really want to) is the usual one: change the
line speed all the way down and send NULLs for a while.
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From: BILLW@SRI-KL
Set the terminal speed to 50 baud (eg: as low as possible), and send a nul.
Most systems need only a framing error to think they have received a break,
and this procedure will certainly generate those !
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From: Richard Kenner <KENNER.CMCL1@NYU.ARPA>
Simplest way is to set the baud rate to at least half the speed you are running
and send a null. Then set the baud rate back.