From owner-freebsd-questions Thu Jul 3 06:38:03 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id GAA09967 for questions-outgoing; Thu, 3 Jul 1997 06:38:03 -0700 (PDT) Received: from ns.ge.com (ns.ge.com [192.35.39.24]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id GAA09962 for ; Thu, 3 Jul 1997 06:37:57 -0700 (PDT) Received: from thomas.ge.com (thomas.ge.com [3.47.28.21]) by ns.ge.com (8.8.4/8.7.3) with ESMTP id JAA12520; Thu, 3 Jul 1997 09:34:30 -0400 (EDT) Received: from crissy.gemis.ge.com (crissy-ether.gemis.ge.com [3.29.7.204]) by thomas.ge.com (8.8.4/8.7.5) with SMTP id JAA15472; Thu, 3 Jul 1997 09:33:57 -0400 (EDT) Received: from ns01.salem.ge.com (ns01.salem.ge.com [3.29.12.4]) by crissy.gemis.ge.com (8.6.11/8.6.11) with ESMTP id JAA26911; Thu, 3 Jul 1997 09:27:12 -0400 Received: from combs.salem.ge.com (combs.salem.ge.com [3.29.5.200]) by ns01.salem.ge.com (8.8.5/8.8.5) with ESMTP id JAA20125; Thu, 3 Jul 1997 09:27:12 -0400 (EDT) Received: from combs (localhost [127.0.0.1]) by combs.salem.ge.com (8.8.5/8.8.5) with ESMTP id JAA02288; Thu, 3 Jul 1997 09:27:10 -0400 (EDT) Message-ID: <33BBA8AC.3F1B76CE@gemis.ge.com> Date: Thu, 03 Jul 1997 09:27:09 -0400 From: "Stephen F. Combs [Network Services]" Organization: GE Motors & Industrial Systems, GEDS, Salem, VA. X-Mailer: Mozilla 4.01b6C [en] (X11; I; SunOS 4.1.4 sun4c) MIME-Version: 1.0 To: Wes Peters CC: "Andrew K. Adams" , questions@FreeBSD.ORG Subject: Re: TrueTime GPS... X-Priority: 3 (Normal) References: <199707020030.UAA05757@wraith.psc.edu> <199707030716.BAA04660@obie.softweyr.ml.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-questions@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk I've been evaluating a "TrueTime" Model NTS-100 for the last couple of weeks (GPS Receiver with a network interface so you don't have to have any specific S/W, just point your ntp S/W at it as a "server") and I must say I haven't been tooooo terribly impressed. It locks on to the satellite(s) just fine (after I FINALLY found a good location for the antenna!) but it's network response Sucks! I've put it's AUI i/f on a Cisco Catalyst switched-hub (it's own dedicated connection) wich is directly attached to our FDDI campus ring. 10 pings of 100bytes result in response times of 39ms to 256ms with AT LEAST 2 packets dropped! I attach a FBSD PC to the same port (using the SAME Twisted-Pair-to-AUI tranceiver AND the same CAT-5 Cable) and get sub-2ms response times for 1000 packets of 100bytes with NO dropped packets!! I have three "stratum-5" ntp servers which sync to three machines in our corporate FireWall office which work just fine. The NTS-100 is currently driving 3 other NTP servers (it's a 'stratum-1' server, so the three machines I have sync'ing to it are at 'stratum-2') which CONSTANTLY loose syncronization with it! For $4300 I'm NOT impressed!!!! I'm using a combination of FreeBSD and Sun Sparc systems as my NTP servers for BOTH set-ups! Running 'xntp3-5.90' on ALL systems. Wes Peters wrote: > Andrew K. Adams writes: > > I would like to attach a GPS to a FreeBSD box (for network > > synchronization) and would be very appreciative of any information > > anyone can offer. I am currently looking at a model manufactured > by > > TrueTime (XL-DC 600), since it (and my PC) is rack-mountable and it > > > provides a serial port for communication -- I am unsure if the > latter > > is useful with FreeBSD. > > Chances are pretty good it is a NMEA-0183 port, which uses RS-422 > signalling levels. You should be able to plug it into a PC serial > port, > unless you have really bad hardware. > > You'll have to contact the manufacturer for information on the > protocol > they use. There is *some* standardization in this area, but I > wouldn't > count on your software working with it. Most manufacturers are pretty > > good about releasing protocol specs, though I've never heard of > TrueTime. > > (I'm known as Barnacle Wes in another, *much* slower dimension. ;^) > > -- > "Where am I, and what am I doing in this handbasket?" > > Wes Peters > Softweyr LLC > http://www.xmission.com/~softweyr > softweyr@xmission.com -- ---- Stephen F. Combs Internet: CombsSF@Salem.GE.COM GE Industrial Systems Voice: 540.387.8828 Network Services Home: CombsSF-Home@Salem.GE.COM 1501 Roanoke Blvd FAX: 540.387.7106 Salem, VA 24153 LapTop: CombsSF-Mobile@Salem.GE.COM