From owner-freebsd-current Thu Dec 16 12:53:16 1999 Delivered-To: freebsd-current@freebsd.org Received: from rover.village.org (rover.village.org [204.144.255.49]) by hub.freebsd.org (Postfix) with ESMTP id 0CCF315782 for ; Thu, 16 Dec 1999 12:53:13 -0800 (PST) (envelope-from imp@harmony.village.org) Received: from harmony.village.org (harmony.village.org [10.0.0.6]) by rover.village.org (8.9.3/8.9.3) with ESMTP id NAA92692; Thu, 16 Dec 1999 13:53:11 -0700 (MST) (envelope-from imp@harmony.village.org) Received: from harmony.village.org (localhost.village.org [127.0.0.1]) by harmony.village.org (8.9.3/8.8.3) with ESMTP id NAA74078; Thu, 16 Dec 1999 13:53:11 -0700 (MST) Message-Id: <199912162053.NAA74078@harmony.village.org> To: nate@mt.sri.com (Nate Williams) Subject: Re: HEADSUP: ntp4 to replace xntpd Cc: "FreeBSD Current Users' list" In-reply-to: Your message of "Thu, 16 Dec 1999 13:48:08 MST." <199912162048.NAA21039@mt.sri.com> References: <199912162048.NAA21039@mt.sri.com> <199912162043.NAA20958@mt.sri.com> <199912162035.NAA20788@mt.sri.com> <199912161810.LAA19919@mt.sri.com> <16818.945366687@critter.freebsd.dk> <199912162032.NAA73759@harmony.village.org> <199912162041.NAA73896@harmony.village.org> <199912162046.NAA74003@harmony.village.org> Date: Thu, 16 Dec 1999 13:53:11 -0700 From: Warner Losh Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <199912162048.NAA21039@mt.sri.com> Nate Williams writes: : > : Cool. I was under the impression that the cheap NMEA signals only gave : > : 2-5sec accuracy given the 2400 baud speed issues. : > : > If you have a PPS signal, then you can get fairly close even if the : > inforation about the PPS signal comes in at 2400 baud. : : Hmm, how do I find out how good it is? By looking at the docs to see if it supports PPS or not. PPS is Pulse Per Second and is a dedicated signal that pulses (typ 10mS) once per second. For serial devices, this is typically done by one of the extra RS-232 signals, DSR comes to mind. I suppose you could hook a scope up to the unit and see if any of the signals are acting like PPS. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message