From owner-freebsd-questions Tue Nov 24 09:06:10 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id JAA13103 for freebsd-questions-outgoing; Tue, 24 Nov 1998 09:06:10 -0800 (PST) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from pau-amma.whistle.com (s205m64.whistle.com [207.76.205.64]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id JAA13098 for ; Tue, 24 Nov 1998 09:06:09 -0800 (PST) (envelope-from dhw@whistle.com) Received: (from dhw@localhost) by pau-amma.whistle.com (8.9.1/8.9.1) id JAA08381; Tue, 24 Nov 1998 09:03:20 -0800 (PST) (envelope-from dhw) Date: Tue, 24 Nov 1998 09:03:20 -0800 (PST) From: David Wolfskill Message-Id: <199811241703.JAA08381@pau-amma.whistle.com> To: questions@FreeBSD.ORG, vr@dnt.md Subject: Re: break signal, off the subj. In-Reply-To: Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >Date: Tue, 24 Nov 1998 18:20:12 +0000 (GMT) >From: Veaceslav Revutchi >what is the break signal (character). You had it right the first time -- it's a signal, not a character. >How do you type it? To be more specific, one >would use it to interrupt the booting process of a cisco router. >tjanks in advance and sorry for posting this question here. A "break" generates a "framing error" -- that is, a sequence of consecutive 0 bits that cannot possibly correspond to any valid character. For example, suppose you're using 8-bit characters, 1 start bit, and a stop bit, no parity ("8N1"). In that case, you actually send 10 bits down the wire for each character, and the first and last of those 10 bits *must* be 1 bits; the others might be any combination of 0 or 1 bits. Thus, if you send at least 9 consecutive 0 bits, that should generate a framing error. For thoroughness, you'd probably want to send at least 10 consecutive 0 bits. That is equivalent to what the "break" key does on a normal ASCII keyboard. david -- David Wolfskill UNIX System Administrator dhw@whistle.com voice: (650) 577-7158 pager: (650) 371-4621 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message