Date: Sun, 15 Oct 2000 23:04:52 +0100 (BST) From: Andrew Gordon <arg@arg1.demon.co.uk> To: Hellmuth Michaelis <hm@kts.org> Cc: David Hedley <david@inty.co.uk>, isdn@FreeBSD.ORG Subject: Re: error messages... Message-ID: <Pine.BSF.4.21.0010152250530.539-100000@server.arg.sj.co.uk> In-Reply-To: <20001014101345.BD66F9B20@bert.kts.org>
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On Sat, 14 Oct 2000, Hellmuth Michaelis wrote: > David Hedley wrote: > > > Is there a reference which explains cable termination? > > Not that i know of. There is a german ISDN cabling FAQ from de.comm.isdn.* > but i know of nothing in english. There's something in english at: http://www.adelheid.demon.co.uk/isdnwire.html > > We have long cable > > runs from the NT to 2 PCI Fritz cards. If both Fritz cards are plugged in, > > both get hundreds of CRC errors. If either one is unplugged then everything > > works fine. > > This seems to be a classic case of one cable being wired somehow wrong. I also note that AVM cards I've bought recently have had extremely long cords with them (about 6m long!): even with a correctly terminated bus, plugging one of these long cords into the middle may be enough to cause unacceptable reflections. > > I have been told that the NT can be switched into 'high power' > > mode to allow for longer cable runs It's not high power, it's a timing adjustment. But it only applies to the case of a single device at the end of a very long run (up to 800m); not for multiple devices. This is the switch labelled "S" and "L" (for "short" and "long") under the cover of the BT NTE8A. Should be in the "S" position for all normal uses. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message
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