Date: Fri, 1 Nov 1996 17:14:56 +0100 (MET) From: Greg Lehey <grog@lemis.de> To: jdunham@fc.net (Jerry Dunham) Subject: Re: Any ISDN-BRI cards work under FreeBSD? Message-ID: <199611011615.RAA20691@freebie.lemis.de> In-Reply-To: <199611011539.JAA24539@freeside.fc.net> from Jerry Dunham at "Nov 1, 96 09:39:13 am"
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Jerry Dunham writes: > Greg Lehey babbled: >> From: Greg Lehey <grog@lemis.de> >> Date: Fri, 1 Nov 1996 08:49:56 +0100 (MET) >> >> Hellmuth Michaelis writes: >>> >>> They will not work in the US, simply because in Europe the NT is supp= lied >>> by the Telecom's whereas in the US the NT has to be supplied by the u= ser >>> or by the device; the "user" interface in Europe is the S0 bus, in th= e >>> US it is the Uk0 interface. A Teles bought in Europe has a S0 interfa= ce. >> >> This doesn't mean they won't work. This means that you need an NT. >> You need an NT here too, but as you say, in Germany it's supplied by >> the PTT. > > What's an NT? I KNOW you're not talking about Uncle Bill's OS. Does Uncle Bill have an OS? An NT is a Network Terminator. Strictly speaking, at least according to my documentation, what I'm talking about is an NT2. It's basically the closest thing that ISDN has to a modem, but most people wouldn't see it that way: it's the interface between the T reference point, which connects between your premises and the central office, and the S reference point, which is what you connect your ISDN devices to. There's also an NT1 in the central office which interfaces between the T reference point and the U reference point, but since just about nobody ever sees them, the term NT has become popular to refer to an NT2. In Germany, people tend to call them NTBAs (Network Terminator f=FCr Basis-Anschlu=DF--how's that for a logical name?), since that's what's written on them. For all I know there's been a change of terminology since my reference books (which are based on the Blue Book) were printed. The term "reference point" needs some explaining. Typically, it's a cable (the T reference point is basically the incoming phone wire) or a bus (the S reference point is what the Germans sometimes call S0, when it's a BRI) to which you can connect multiple devices. The big difference between the T reference point and the S reference point is electrical rather than logical, so the NT2 mainly needs to provide relatively simple electrical conversions. Greg
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