From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Schefter Subject: Re: Null X.25 cable? Date: Fri, 14 May 2004 09:30:45 -0400 Sender: linux-x25-owner@vger.kernel.org Message-ID: <40A4CA05.7000501@wanware.com> References: <129179533859.20040514122213@rootelecom.ru> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <129179533859.20040514122213@rootelecom.ru> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: un@rootelecom.ru, linux-x25@vger.kernel.org Hi. > Is there any way to connect two X.25 card directly via cable (may be > NULL MODEM)? > If yes, what configuration of connectors it must have? > Will two cards (configured as DTE) work together? > > If anyone knows, please help! The short answer is yes. But in order for this to work, there are a few things you need to check. First, the card must be capable of being internally clocked. One side will need to be setup as internal and the other as external. Second, make sure you use a synchronous null modem cable. The more common async null modem won't route the clocks properly between the two sides (it just crosses the data and control signals). You'll need to make sure that the "I" side of the null modem goes to the side that has the clocking set to internal. Third, there are two concepts of DTE and DCE in X.25: physical and logical. The null modem will take care of the fact that you are connecting two physical DTEs together, but you also need to change the logical setting (in software) to DCE on one side. You can find the pinout for null modem cables for various electrical interfaces on our website under "support". There's also an application note covering this topic on our website: http://www.wanware.com/index.php?page=support/app_notes/mach2mach&menu=support Regards, 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