SUMMARY: Sending a 'BREAK'

From: Jason Hargis (Jason.Hargis@PII.COM)
Date: Mon Nov 22 1993 - 01:30:38 CST


Original Question:

        I am in the process of connecting several Sun workstation's
        serial 'console' ports up to a Network terminal server. Once
        complete this will be great for administration, as I will have
        total control over each workstation from anywhere. The only
        problem I have (so far) with this setup is that I am unable to
        send a 'break' signal to the workstation that is on the
        Terminal server (to put it into monitor mode). I am attempting
        this from Openwindows on the Console of my server while I am in
        an "xterm" window. I would like to know HOW and WHAT "keys" on
        the sun keyboard I should map to send a BREAK signal. I have
        looked at examples of using 'xmodmap', however I have been
        unable to get the desired result. Can anyone help?

Answer's:
---------
Many people suggested something like the following:

>If you get to it via telnet, something like ^] send brk
>may do it. If you're using Sun's tip program to talk to serial ports
>on a Sun, send ~# at the beginning of a line.

I tried this and it works for what I am attempting to do.

>From miker@il.us.swissbank.com:

>How are you connecting into the terminal server's serial port? tip, for
>example uses the tilde/# sequence. Check your terminal server's manuals.

Using the telnet 'break' did the trick.

>From rlyle@nl.oracle.com:

>You'll have to make sure the terminal server doesn't intercept the break and
>give you a terminal server prompt!! Other than that, what's wrong with
>using a resource definition for your Xterm ie.

>Xterm*VT100.translations: #override \
        <Key>F1: string(0x1b) string("[1~") \n\
        <Key>Home: string(0x1b) string("[1~") \n\
        <Key>F2: string(0x1b) string("[4~")

>Insert your favourite BREAK code for the key/string combination you desire.

I didn't try it, however it looks like that would work too!

>From jpl@allegra.att.com:

>...the ``total control over each workstation'' joy must be
>tempered by the possibility of hosing every workstation at the
>same time. If you have not already do so, verify the effect of
>power-cycling and simply rebooting your terminal server. On
>some devices (Sun's serial line boxes, for example), a reboot
>causes a break to go out on every serial line.

I haven't tested this YET, however thanks for warning!

                                Thanks to all who responded,

                                        Jason Hargis
                                        Corp. UNIX Systems Admin.



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