SUMMARY: Problems w/ modem port...

From: Richard J. Niziak (sunne!rickn@abvax.icd.ab.com)
Date: Tue Jan 21 1992 - 18:53:56 CST


Previously, I wrote:
>
> System: Sparc1
> OS 4.1.1b
> Modem Telebit T2500
>
> Problem:
> Recently, we enabled dial back access on our telebit (S46)
> It seemed to work fine for a while until last week, when for some
> reason or another the port seems to have a login process running
> on it... like this:
>
> root 17494 2.7 0.8 40 324 ? S 11:57 0:00 login -p nne loin:
>
> and I get this type of error mssg in my concole:
>
> Jan 20 11:57:45 sunne init: '/usr/etc/getty std.19200 ttya' failing, sleeping
> Jan 20 11:58:19 sunne login: REPEATED LOGIN FAILURES ON ttya, loginlno
> Jan 20 11:58:35 sunne login: REPEATED LOGIN FAILURES ON ttya, o_

THe problem was w/ the S131 register on the Telebit..

I switched it from 2 to 1 and the problems went away..

A techie from telebit helped me w/ it.

It is a switch that defined the Data Carrier Detected (DCD) signal
interpretation, options are as follows:
0 DCD is always on
1 DCD is on only when a carrier is detected from a remote modem
2 DCD is on only when the modem is ready to accept commands or data
3 DCD is on when the modem is ready to accept commands or data.
        When carrier is lost, DCD is turned off for the amount of time
        specified by the S47 register (default is 200 miliseconds), then
        is turned on.
4 DCD is the inverse of CTS in command and online modes.
        Recommended for use in transparent synchronous mode only.

Rick Niziak
UNIX System Coordinator
Allen-Bradley Company, Inc



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