From owner-freebsd-isdn Thu Mar 26 05:54:14 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id FAA07556 for freebsd-isdn-outgoing; Thu, 26 Mar 1998 05:54:14 -0800 (PST) (envelope-from owner-freebsd-isdn@FreeBSD.ORG) Received: from linteuto.teuto.de (linteuto.teuto.de [194.77.23.26]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id FAA07488 for ; Thu, 26 Mar 1998 05:53:46 -0800 (PST) (envelope-from martin@rumolt.teuto.de) Received: from rumolt.teuto.de (root@rumolt.teuto.de [194.77.23.161]) by linteuto.teuto.de (8.8.8/8.8.8) with ESMTP id OAA03425; Thu, 26 Mar 1998 14:52:33 +0100 Received: (from martin@localhost) by rumolt.teuto.de (8.8.8/8.8.7) id JAA05450; Thu, 26 Mar 1998 09:26:51 +0100 (MET) From: Martin Husemann Message-Id: <199803260826.JAA05450@rumolt.teuto.de> Subject: Re: Fax To: etonumo@eto.ericsson.se (Ulltveit-Moe Nils) Date: Thu, 26 Mar 1998 09:26:51 +0100 (MET) Cc: simons@rhein.de, freebsd-isdn@FreeBSD.ORG In-Reply-To: <9803251001.AA18606@dinosaur> from "Ulltveit-Moe Nils" at Mar 25, 98 11:01:24 am Organization: Crusaders Catering Services Inc. X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: owner-freebsd-isdn@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > This is probably not implemented. No, it is not implemented. > Implementing G3 fax in ISDN would mean simulating an analog modem > on the digital link. This means having to generate the right waveforms > for the modulated data, and receive analog data from the other end > which you had to run FFT analysis on and then interpret. Probably not an FFT, a simple IIR filter might do (but I'm not good enough in signal proccessing to be sure) > In addition you have to do this in realtime, to be able to deal with > the timing involved in the fax protocol, something neither > FreeBSD or Linux is good at in their native form.. Not that hard real time. You know, you can do this on a 486/33 running Windows 3.1 - so you realy should be able to do this on any BSD with a 486 or better. I once looked at doing this (and might reconsider doing it just for fun if I get hold of all the neccessary standards for less than a few thousand dollars). I use an active card (with very limited on-board resources) and would try to handle at least parts of the d/a and a/d, if not all of the G3 protocol, on the card itself. But since you can't easily debug there, I would first implement a pure kernel based version. Anyway, your real point "use dedicated hardware" is correct. That's why I have a paper fax now. Martin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message