Administering a system remotely can be done for a workstation  booted off its serial port A or port B. This can be done with
 direct connections (dumb terminal or sparc station) or  indirectly using telnet. In the latter case, a serial connection from A or B must be made to a Network Terminal Server or Contentrator. (Telneting to a pseudo-tty will not  allow sending a break signal as it is not a console device.)

 1) Using telnet:

   telnet to host and log in. To get to the 'telnet>' prompt
   press:

         <ctrl>-]

   Then type:

           send brk
   or
           send break  (depending on terminal concentrator requirements)
 

 2) Using a direct connection to generate a BREAK signal on the line:

   Use either 'kermit' or 'tip' (in a shell tool) to connect
   to /dev/cua/a. The connection is made via a null-modem serial cable  to the A or B port of the workstation to  be administered.

   If using 'tip', press <RETURN><TILDE><POUNDSIGN>

           <CR>~#

   In 'kermit', the sequence is control-backslash-B

           ^\B
 

After much discussion, it has been decided to alter the code sequence that is required to produce "STOP-A" functionality via the serial console port. The new sequence
 is

 <RETURN> <TILDE> <CONTROL-B>

 It is highly unlikely that this will every be generated erroneously. As a further safeguard, it is time-limited. There must be more than 0.5 seconds between characters, and
 the string must be entered in less than 5 seconds.

 The new functionality is enable by changing the /etc/defayult/kbd file:

 #KEYBOARD_ABORT=enable

 to

 KEYBOARD_ABORT=alternate

 or alternatively, as root, running the command

 # kbd -a alternate
 

 The change is available as follows:

 2.5.1 or lower - upgrade to 2.6 or better
 2.6            - requires patch 105924-10 or later
 7              - requires patch 107589-02 or later
 8              - functionality is already integrated.

Sources:

 Ben Humphreys <benh@zipworld.com.au>
 James McPherson <James.McPherson@Aus.Sun.COM>

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