Vt320 Xon XoffHello,

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2 total messages Started by Philip Macdonald Thu, 05 Nov 1992 21:13

#984

Author: Philip Macdonald
Date: Thu, 05 Nov 1992 21:13

22 lines
1313 bytes

	This may be a FAQ but here goes anyway.  I've setup
	some VT320 to talk to a DEC server. I've noticed that
	when users connect to a UNIX account and run EMACS
	strange things happen. The down arrow key causes the 
	EMACS to flip out after a few "DOWN ARROWS". I attributed
	this to the XON XOFF flow control. If I set flow control
	to off things work great. The problem is that when this
	is set to off the "HOLD SCREEN" button and LED are disabled.
	Control-S will hold the screen but not light the HOLD SCREEN
	LED. Now if a user hits Control-S when they ment to hit
	Shift-S the screen freezes and they are stuck.

	What I need to know is:
	What kind of setup do you need to talk to EMACS and IRC (for that
        matter) without having Xon=OFF?

				Thanks in advance,
				Phil
				pmacdon@husc10.harvard.edu

Re: Vt320 Xon XoffHello,

#993

Author: Doug Gwyn
Date: Thu, 12 Nov 1992 17:08

20 lines
1751 bytes

In article <pmacdon.720998015@husc10> pmacdon@husc10.harvard.edu (Philip Macdonald) writes:
>	This may be a FAQ but here goes anyway.

Yes, it's a classic issue.
Many modern ASCII terminals require host support for DC3/DC1 flow control
in order to not overrun their input buffer while performing time-consuming
operations such as insert line, smooth scroll, etc.  The VT100 was the first
widely used terminal like this.
Unfortunately some of the EMACS hackers, Stallman for example, insisted
that terminals should not behave that way and consequently refused (at
least for a long time) to make their versions of EMACS properly support
DC3/DC1 in-band flow control.  For example, on most UNIX systems the user
(or system administrator) is supposed to arrange for DC3/DC1 flow control
to be handled by the operating system's terminal handler when the user
logs in -- subsequent processes like EMACS then should preserve that mode
when fiddling with the terminal handler settings for their particular
style of screen and keyboard management.  Unfortunately many such programs
do not do this right (and some UNIX systems didn't support doing it right).
I don't know which version of EMACS you have but there should be some way
to force it to work right, even if it means editing the source code.

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