From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263510AbTDGPDT (for ); Mon, 7 Apr 2003 11:03:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263509AbTDGPDT (for ); Mon, 7 Apr 2003 11:03:19 -0400 Received: from pc2-cwma1-4-cust86.swan.cable.ntl.com ([213.105.254.86]:61332 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S263507AbTDGPDS (for ); Mon, 7 Apr 2003 11:03:18 -0400 Subject: Re: modifying line state manually on ttyS From: Alan Cox To: Michael Buesch Cc: Linux Kernel Mailing List In-Reply-To: <200304071702.08114.freesoftwaredeveloper@web.de> References: <200304071702.08114.freesoftwaredeveloper@web.de> Content-Type: text/plain Content-Transfer-Encoding: 7bit Organization: Message-Id: <1049724987.2965.60.camel@dhcp22.swansea.linux.org.uk> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 (1.2.2-5) Date: 07 Apr 2003 15:16:28 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Llu, 2003-04-07 at 16:02, Michael Buesch wrote: > I have developed my own device, that is connected to ttyS0. > To talk to my device, I need to set the state of the TxD line > manually to either 0 or 1 (+12v or -12v). What I try to say is, TxD is a bad choice. A lot of the hardware cannot control TXD this way. DTR is the usual one because it is easy to handle but there are other control lines you can drive directly (see TIOCGMODEM)