From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Robin Gilks" Subject: Re: Packet at the physical level Date: Fri, 19 Sep 2003 10:37:40 +1200 (NZST) Sender: linux-hams-owner@vger.kernel.org Message-ID: <53174.202.37.96.11.1063924660.squirrel@server> References: <20030918190546.GB3466@n7xy.net> Reply-To: robin@gilks.org Mime-Version: 1.0 Content-Transfer-Encoding: 7BIT Return-path: In-Reply-To: List-Id: Content-Type: text/plain; charset="us-ascii" To: linux-hams@vger.kernel.org Greetings To get a view of the physical layer just above the tones themselves, take a look at the bit-bashing in the TVIPUG (Thames Valley IP User Group) 9k6 modem. This does all the NRZ/NRZI conversion, the CRC generation and checking, the bit stuffing and stripping on a bit level (makes it a bit clearer than byte level I think!!). Its also independent of the speed and avoids the pitfall of thinking all packet being at 1200bps :-)) http://www.tvipug.org/download/ipri-1.00.tar.gz > I'm trying to find out what happens at the physical level with > Ax25 packet. I've tried looking at the source code but either I'm > looking in the wrong place, or I don't understand. > -- Robin Gilks Internet: robin@gilks.org http://www.gilks.org Tel: (+64) (3) 357 9383