From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Schefter Subject: Re: Null X.25 cable? Date: Mon, 17 May 2004 09:29:11 -0400 Sender: linux-x25-owner@vger.kernel.org Message-ID: <40A8BE27.7020606@wanware.com> References: <1a4.23eb82b5.2dd7cc89@aol.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1a4.23eb82b5.2dd7cc89@aol.com> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: TProvoni@aol.com Cc: un@rootelecom.ru, linux-x25@vger.kernel.org Hi Joachim. > Wanware hardware sounds somewhat restrictive in its clock > configurations. I have worked with several vendors' equipment that > allows symmetric independent clocking. Transmit clocks are sent from > both sides and the receivers extract the clocks as they receive data. We support that as well. It is just more common to have the physical DCE generate the clock for both sides to use (such as when you are connected to a modem or DSU/CSU). I generally only put internal clocking on both sides when I'm using FM0 line encoding. > BTW, some specifications provide a third sense of DTE and DCE in terms > of connector definition. > > Thus it is possible to use a DCE connector on the interface that is a > DTE in the clock sense and a DCE in the protocol sense. When you say the DCE is "DTE in the clock sense", do you mean it's externally clocked? (And you didn't like my arbitrary selection of DTE as externally clocked above ;-) Just to be clear, there's the selection of: - physical DTE versus physical DCE - logical DTE versus logical DTE - who will provide the clock All three of these are independently chosen. You can mix and match and get lots of combinations. Steve ------------------------------------------------------------------------ Steve Schefter phone: +1 705 725 9999 x26 The Software Group Limited fax: +1 705 725 9666 642 Welham Road, email: steve@wanware.com Barrie, Ontario CANADA L4N 9A1 Web: www.wanware.com