From owner-freebsd-questions@FreeBSD.ORG Tue Sep 15 08:11:35 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B73DD1065670 for ; Tue, 15 Sep 2009 08:11:35 +0000 (UTC) (envelope-from perryh@pluto.rain.com) Received: from agora.rdrop.com (unknown [IPv6:2607:f678:1010::34]) by mx1.freebsd.org (Postfix) with ESMTP id 8A8298FC08 for ; Tue, 15 Sep 2009 08:11:35 +0000 (UTC) Received: from agora.rdrop.com (66@localhost [127.0.0.1]) by agora.rdrop.com (8.13.1/8.12.7) with ESMTP id n8F8BYEO096319 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Tue, 15 Sep 2009 01:11:35 -0700 (PDT) (envelope-from perryh@pluto.rain.com) Received: (from uucp@localhost) by agora.rdrop.com (8.13.1/8.12.9/Submit) with UUCP id n8F8BY1g096318; Tue, 15 Sep 2009 01:11:34 -0700 (PDT) Received: from fbsd61 by pluto.rain.com (4.1/SMI-4.1-pluto-M2060407) id AA08079; Tue, 15 Sep 09 01:01:47 PDT Date: Tue, 15 Sep 2009 01:04:38 -0700 From: perryh@pluto.rain.com To: rsmith@xs4all.nl Message-Id: <4aaf4a96.rnIcIpF47vYAtgHm%perryh@pluto.rain.com> References: <20090914173420.GB69286@slackbox.xs4all.nl> <19118.36021.489954.856994@jerusalem.litteratus.org> <20090914230620.2f7dd3d4.freebsd@edvax.de> <20090914224038.GA77585@slackbox.xs4all.nl> In-Reply-To: <20090914224038.GA77585@slackbox.xs4all.nl> User-Agent: nail 11.25 7/29/05 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: freebsd-questions@freebsd.org Subject: Re: rebinding keys to functions X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Sep 2009 08:11:35 -0000 Roland Smith wrote: > Writing a driver to detect if headphones are connected sounds > much more complicated to me than connecting a couple of switches! > I mean, you'd have to measure something like the impedance of > the jack. Surely that is more expensive than a simple switch? Or use a simpler jack, with one switch that connects to ground or not depending on whether the plug is inserted or not. It probably costs a cent or two less than the usual two-switch variety, and this is a BOM (Bill Of Materials, i.e. per-unit-built) savings. Writing the driver is an NRE (non-recurring engineering) expense which can be amortized over -- the manufacturer hopes -- a huge number of delivered units.