Login Problem (250' RS-232 Lines)

[Phil Ngai]

In article <604 at oliveb.UUCP> jerry at oliveb.UUCP (Jerry Aguirre) writes:
>If you connect the Data Terminal Ready (DTR) of the terminal to the Data
>Set Ready (DSR) of the computer port, then the getty will not send login
>messages to terminals that are turned off.  Nor will it listen to
>garbage on the line.

We found that in our environment, where people had switch boxes to select
between their Unix port and a CP/M system, noise would couple onto the
DSR lines just like it coupled onto the computer's RxD line. This had the
effect of someone calling up a dialup modem and hanging up, over and over.
The getty spawning made the computer run slowly.

I suppose if your users didn't effectively disconnect the terminal line
on a daily basis, using DSR might work. Or if your environment were less
noisy than ours.

-- 
 Arthur Rudolph believed that technology is morally neutral and so,
therefore, are those who create it.

 Phil Ngai +1 408 749-5720
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