Break Key

Tuesday, December 30, 2008 03:41 pm administrator

AbsoluteTelnet/SSH supports a number of flavors of 'break' depending on the type of connection in use.  AbsoluteTelnet can send breaks on serial ports and modems as well as in telnet and SSH2 sessions (sorry, no specification exists for sending breaks in SSH1 mode).   A break is always sent by hitting the ctrl-break key combination.

Serial Break:  AbsoluteTelnet sends a serial break when using a serial port or a modem.  The duration of the break signal is 1000ms.

Telnet Break:  When in a telnet connection, AbsoluteTelnet sends a telnet break in accordance with RFC854.  RFC854 does not include a mechanism for setting the break duration.

SSH2 Break: When in an ssh2 connection, AbsoluteTelnet sends a break in accordance with RFC4335.  SSH2 breaks allow the specification of the break duration.  The default duration for SSH2 breaks in AbsoluteTelnet is 500ms.


Break signals are sometimes required on the host side to access special menus or administrative functions.  Many times, it is interpreted as a command to terminate a program running on the remote host.  AbsoluteTelnet/SSH can send the break signals that are required for these functions, but the interpretation of the break and the action taken is completely host specific.