[ntp:questions] ntp server specs

unruh unruh at wormhole.physics.ubc.ca
Wed Jun 15 08:54:36 UTC 2011


On 2011-06-14, David Woolley <david at ex.djwhome.demon.invalid> wrote:
> unruh wrote:
>
>> (or rather impedance matching chip) and some lines (eg 50 ohm cat5
>
> Cat 5 is at least 100 ohm.

Oops you are right. It is 100 ohm, not 50. (memory...) So if you have a
loger run (> 30m) you had better make sure you terminate the cable at
the computer end with a 100 ohm or you will get reflections which could
mess up the timing ( assuming you are interested in usec precision) If
it is longer than 100m, you had better worry about cable delay as well
(about 5ns/m).







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