[ntp:questions] Re: tinker step 0 (always slew) and kernel time discipline

David Woolley david at djwhome.demon.co.uk
Sat Sep 23 08:16:37 UTC 2006


In article <bbednfUcuLsg0InYnZ2dnUVZ_vSdnZ2d at comcast.com>,
Richard B. Gilbert <rgilbert88 at comcast.net> wrote:

> The telephone companies tend to be very aware of time and timing.  The 
> time division multiplexing of T1 and T3 lines requires splitting the 
> second very precisely.  Cellular phones also require very precise 

That can be true of the public network, although even then it may
be more so for the more engineering oriented layers, like bearer
synchronisation, than the more commercial oriented layers, like
call detail recording.

However, it is very definitely not true of most PABX systems, which
typically have wristwatch and eyeball set times and run in local
time, with no automatic daylight saving switch, and have no high quality
frequency standard.

At least one PABX type consistently gets the start time wrong, even if
it its clock is set properly.




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