> From: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> > Date: Mon, 05 Nov 2007 16:34:02 -0800 > Sender: [EMAIL PROTECTED] > > > My NTP server is run at the local phone company. They already have a > GPS fed stratum 2 (?) time source fed via GPS on the roof. The CO guy > told me that they have lots of leads off their "composite clock" and > we could have one if we needed. Apparently this timing source feds all > their telco gear (OC-X equipment, class 5 switch, etc). > > I asked him what I should google up and he said "composite clock." Is > there some way to hook up a "composite clock" to the serial port on my > server? It appears that a composite clock is three wires: tip, ring > and ground? Any help on if it's possible to use this would be great.
This looks like it's probably a T1 connection to provide sync, not time, to telco equipment. Telcos think of "clock" as a highly synchronized T1 clocking signal to keep all of their equipment in sync. It provides very accurate clocking to ADMs, routers, switches and the like, but does not provide actual time. The GPS is used to assure that the clocking is consistent around the world. Make sure that they are providing time code, not just a clock signal. IF they are, it is most likely IRIG-B timecode and there are several ntpd supported reference clocks that support IRIG-B. We went through this last year when we moved our colos to a new provider and they told us that they could provide a a GPS based clock. They handed us a T1 and we had to explain that some of use actually want to know what time it is, not just how fast time is passing. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: [EMAIL PROTECTED] Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751
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