[comp.unix.aix] TTY line problem

guarna@uicsrd.csrd.uiuc.edu (12/28/89)

I just added the IBM Dual Async board to my Model 80 running AIX.  I have a
terminal on one of these lines (tty2) using a three wire interface.  Everything
seems to work fine until I turn the terminal off.  When I turn it on later
to try and use the terminal again, the line won't communicate. I think this is
a baud rate problem...I get question marks on the screen for each keypress.
My terminal generates those when it gets framing/parity/etc. errors.

If I pdisable and penable the tty line, all is well and I get the
logon banner again.  Has anyone else seen and solved this problem?

	Vince Guarna
	University of Illinois
	(217) 244-0071
	guarna@uicsrd.csrd.uiuc.edu

peter@hydrovax.nmt.edu (Peter A. Blemel) (12/29/89)

In article <48200002@uicsrd.csrd.uiuc.edu>, guarna@uicsrd.csrd.uiuc.edu writes...
>... Everything
>seems to work fine until I turn the terminal off.  When I turn it on later
>to try and use the terminal again, the line won't communicate. 

The 135 using a dual rs232 (9pin) adapter configured as sp1,sp2 (primary,
secondary) has a similar problem (I don't think it's baud rate). The getty
will completely forget about the terminal if the terminal is power cycled.
Killing the getty works as init forks a new one, and I get the login prompt
(which is effectively what you do by disable/re-enableing the terminal.)`N[

I intend to putz with the devices configuration some today. I'll post the
results.

Peter
-----
peter@hydrovax.nmt.edu
peter@amber.nmt.edu

johnny@edvvie.at (Johann Schweigl) (01/04/90)

From article <3694@nmtsun.nmt.edu>, by peter@hydrovax.nmt.edu (Peter A. Blemel):
> In article <48200002@uicsrd.csrd.uiuc.edu>, guarna@uicsrd.csrd.uiuc.edu writes...
>>... Everything
>>seems to work fine until I turn the terminal off.  When I turn it on later
>>to try and use the terminal again, the line won't communicate. 

We had similar problems with a model 125 and 135. In our case, excessive noise
was the cause. When a 3151 was switched off, the respective 3-wire RS232 
line was a kind of antenna. Seems the terminal leaves the line ends open when 
not turned on. First action was to use shielded wire and connect everything
to ground that *SHOULD* be grounded. That reduced the problems reasonably.
Second, we switched to RS422. Since then, we have no trouble of this kind.
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