Hi,
The primary need is for the XOs in the school to have the same time (to
a few seonds, even a minute or so, is probably ok. The primary need is
to have information from the XOs be somewhat consistent. The school
server time should also be accurate to a few minutes, of course.
At the moment, it is off by some hours because of problems setting the
time zone. Some of the XOs are off by a day or two.
Once I get XS-0.7 set up (currently using XS-0.6 (NEXS version), it
should be easy to set the school server time. Having a gps stick would
reduce the burden on the school staff to administer although it may be
possible to get low bandwidth access to the internet via a gsm modem
(edge) which could allow ntp synchronization.
What I would really like is a method to allow the XOs to synchronize
with the school server as they connect. This should happen two or three
days a week when school is in session.
Yours,
Tony
On 08/27/2012 08:28 PM, Hal Murray wrote:
In a school deployment, it is desirable that all of the XOs have the same
time. This time should be synchronized with/by the school server (even if
the school server is wrong). It is not reasonable to base this capability
on access to the internet.
How closely do you need them to be synchronized? 1 second? 1 microsecond?
1 minute?
It should be reasonably easy to setup ntpd on the school server and get the
XOs to set their clocks when booted.
You may want/need a cron job to set the time occasionally.
Casio sells 'atomic' watches that synchronize to Ft. Collins by radio.
Neat, but how does this work in Rwanda?
WWVB runs at 60 KHz. There are several similar systems in other countries.
I don't think any of them make it to Africa. GPS does.
You can get USB GPS receivers for under $50. The SiRF chip is the most
popular in the low cost units. It's crappy if you need ms level timing, but
good enough if all you need is 1 second.
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