Date: Sun, 24 Jan 1999 17:26:42 +0100 (MET) From: hm@hcs.de (Hellmuth Michaelis) To: stefhe@gmx.net (Stefan Herrmann) Cc: freebsd-isdn@FreeBSD.ORG Subject: Re: I4B support for US ISDN? Message-ID: <m104SN1-00003OC@hcswork.hcs.de> In-Reply-To: <36AB119D.553C5A99@gmx.net> from Stefan Herrmann at "Jan 24, 99 01:27:09 pm"
next in thread | previous in thread | raw e-mail | index | archive | help
>From the keyboard of Stefan Herrmann: > > On the other hand, from Layer 3 point of view it shouldn't make > > any difference whether its S or U interface. > > What does S and U interface meen and what is the difference ? There are several so called "reference points" defined in the ISDN standard texts, one of them is the S reference point and another is the U reference point. In Germany, when you order an ISDN line, the Telekom provides you with an NT, the side going out to the exchange has an U interface and the other side, where you plug in your devices, has an S interface, == S0 bus. The U interface is point-to-point, uses 2 wires and 2 modulation schemes are available (AFAIK, a german NT will not work in the US and vice versa). The S interface is point-to-multipoint and uses 4 wires. hellmuth -- Hellmuth Michaelis Tel +49 40 559747-70 HCS Hanseatischer Computerservice GmbH Fax +49 40 559747-77 Oldesloer Strasse 97-99 Mail hm [at] hcs.de 22457 Hamburg WWW http://www.hcs.de To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?m104SN1-00003OC>