From owner-freebsd-hackers@FreeBSD.ORG Sun May 11 16:52:22 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2713E37B401 for ; Sun, 11 May 2003 16:52:22 -0700 (PDT) Received: from mail.gmx.net (mail.gmx.de [213.165.64.20]) by mx1.FreeBSD.org (Postfix) with SMTP id DD5BD43FB1 for ; Sun, 11 May 2003 16:52:20 -0700 (PDT) (envelope-from mdcki@gmx.net) Received: (qmail 2980 invoked by uid 65534); 11 May 2003 23:52:19 -0000 Received: from cvpn016.gwdg.de (EHLO gmx.net) (134.76.22.16) by mail.gmx.net (mp018-rz3) with SMTP; 12 May 2003 01:52:19 +0200 Message-ID: <3EBEE274.20105@gmx.net> Date: Mon, 12 May 2003 01:53:24 +0200 From: Marcin Dalecki User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.4a) Gecko/20030419 X-Accept-Language: en-us, en, pl, ru MIME-Version: 1.0 To: ticso@cicely.de References: <2E7E8A35375D1449A6F28D5E022E67310AC4D2@USSC8MS04.Global.Cwintra.Com> <3EBD2F95.9090807@gmx.net> <20030511005127.GD1922@cicely9.cicely.de> <3EBE3CB4.1000401@gmx.net> <20030511123016.GG1922@cicely9.cicely.de> In-Reply-To: <20030511123016.GG1922@cicely9.cicely.de> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: freebsd-hackers@freebsd.org cc: "Yevmenkin, Maksim" Subject: Re: USB link cable? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 May 2003 23:52:22 -0000 Bernd Walter wrote: > > Basicly the device is powered from the USB bus - of which there are > two. > It's quite possible that the vendor of your device failed to handle > that situation correctly. > Basicly it's possible to get an enourmous overvoltage if the +5V line > gets connected before GND and your devices have different GND bases. > Unless the vendor put the required overvoltage protection circuits into > that device and they tried to take power from both sides it's strictly > not hot-plug-able. > OK. After a good half our of cutting through plastic I was able to get a view of the pannel. There are just the 12MHz osc. the main chip and two huge diodes there. And a bunch of passvie elements as usual... There are two spare soldering places for transistors or maybe voltage stabilizators... As much or better as few as I understand from electronics two diodes are of course not enough to provide the necessary electrical overload protection. So I will assume thet your guess is very likely to be right. Thanks for the educated explanation. It was just my experimenting which simply made the accident waiting to happen actually occur. Now my curiousity is satisfyed and I will just have to by a new device...