Subject: Re: what is a serial BREAK ?
To: Manuel Bouyer <>
From: Steven M. Bellovin <>
List: netbsd-users
Date: 06/03/2005 08:30:20
In message <>, Manuel Bouyer writes:
>thanks to all who replied. So a serial break is just a long logical '0'.
>I wasn't sure because sun serial console gets a break when disconnected
>from the terminal or when the terminal is powered off, which lead me to
>think is was related to ground.

This actually goes back to where the word "break" comes from -- a line 
break on a teletype line....  As Johnny Billquist noted, it's somewhat 
arbitrary -- teletypes used a 20 milliamp "current loop", rather than 
RS-232 -- but it was certainly convenient to mimic the old behavior.

		--Steven M. Bellovin,