From owner-freebsd-hackers Sat Dec 9 01:59:43 1995 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id BAA09667 for hackers-outgoing; Sat, 9 Dec 1995 01:59:43 -0800 (PST) Received: from cls.net (freeside.cls.de [192.129.50.1]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id BAA09655 for ; Sat, 9 Dec 1995 01:59:38 -0800 (PST) Received: by mail.cls.net (Smail3.1.29.1) from allegro.lemis.de (192.109.197.134) with smtp id ; Sat, 9 Dec 95 09:59 GMT From: grog@lemis.de (Greg Lehey) Organisation: LEMIS, Schellnhausen 2, 36325 Feldatal, Germany Phone: +49-6637-919123 Fax: +49-6637-919122 Reply-To: grog@lemis.de (Greg Lehey) Received: (grog@localhost) by allegro.lemis.de (8.6.9/8.6.9) id KAA00331 for hackers@freebsd.org; Sat, 9 Dec 1995 10:30:19 +0100 Message-Id: <199512090930.KAA00331@allegro.lemis.de> Subject: Re: Who's working on ISDN? To: chuckr@glue.umd.edu (Chuck Robey) Date: Sat, 9 Dec 1995 10:29:45 +0100 (MET) In-Reply-To: from "Chuck Robey" at Dec 7, 95 11:23:47 pm X-Mailer: ELM [version 2.4 PL23] MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: owner-hackers@FreeBSD.ORG Precedence: bulk Chuck Robey writes: > > I used to be a voice/digital telecomm guy, before I went back to school, > and I'm really curious. I know the European digital pipes are 2.048 MBS, > while ours are 1.544 MBS. I saw above where it said NT1. Are the NT1 > rates the same here/there, or does the card do both 2.048/1.544? The boards we're talking about here are Basic Rate boards, still usually known as S0 in Geramny. The standard is the same everywhere: 2 B channels with 64 kb/s (which can be used for voice or data), one D (signalling) channel with 16 kb/s. Also, for the signalling guys, there's another 48 kb/s channel timing. The NT1 (known in Germany as NTBA) is an active electrical interface to the externatl telephone line. Basic Rate in the US has a problem that the trunks usually run 64 kb/s with inband signalling. As a result, they take one bit per byte of the B channels, and you end up with 56 kb/s B channels. I don't think that German ISDN boards can handle that, though maybe it's a software option. Greg