Path: utzoo!attcan!uunet!pcrat!rick From: rick@pcrat.UUCP (Rick Richardson) Newsgroups: comp.dcom.modems Subject: Re: Autobaud Matching Message-ID: <578@pcrat.UUCP> Date: 20 Sep 88 11:31:36 GMT References: <56.015163@adam.DG.COM> <9262@cup.portal.com> Reply-To: rick@pcrat.UUCP (Rick Richardson) Organization: PC Research, Inc., Tinton Falls, NJ Lines: 26 In article <9262@cup.portal.com> thad@cup.portal.com writes: > >In general, autobaud detection necessitates your system being set up at some >"high" baud and analyzing the bits that arrive when a caller types some >character (typically a carriage return). There are three basic methods: 1) Pattern match the garbage that comes in on the UART. 2) If a USART, put in sync mode, sync char==FF at a bit rate twice the highest speed expected. Then collect the bits and analyze, and restore async mode. 3) Use a UART which supports hardware autobaud, such as AT&T's ARTI (can't remember part no). The ideal, of course, is single character autobaud. I've implemented all three of these methods. They are listed in the order I tried them over the years, which is also the order from worst to best implementation. #3 is patented (I'm one of the inventors) and I don't know if it has been licensed to any other chip manufacturer. -- Rick Richardson, PC Research, Inc. rick%pcrat.uucp@uunet.uu.net (INTERNET) uunet!pcrat!rick (UUCP, Personal Mail) ..!pcrat!jetroff (JetRoff Info) ..!pcrat!dry2 (Dhrystone Submissions)