[ntp:questions] ESR looking for good GPS clocks

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Fri Mar 9 11:20:57 UTC 2012

Kasper Pedersen wrote:
> Terje Mathisen wrote:
>> The more I look at this, the more I settle down on using Ethernet as the
>> communication channel!
>> Something like the Soekris board reduced to the size of a pack of cards,
>> with a (timing) gps chip on a daughter card, and an Ethernet port for
> ...
> You do not need an entire Linux/FreeBSD/* capable box to do this. The
> device only needs to transmit, preferably multicast. This avoids having to
> configure an address on the device.
> I experimented with this some time ago:
> http://n1.taur.dk/etherpps/

Very nice, seems like a very fun hack!

> I also measured the timing across a small business network:
> http://n1.taur.dk/ethertest/
> You are looking at a half-credit-card sized board with a modjack, a
> microcontroller, a GPS module, a SMA connector, and a mini/microusb for
> power. For 100 units, looking what I paid last time I bought small volume
> for the parts, usd50/unit is feasible.
> Then, to sell them, CE/FCC testing needs to be done, and that is usually
> is usd5-10k. Unless there's a loophole that can be used for bare boards.
> /Kasper Pedersen

- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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