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

Hal Murray hmurray at suespammers.org
Sun Sep 24 02:26:44 UTC 2006

>> 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.

There are two separate issues: time and frequency.

Anybody know if I can get a good frequency off a DSL line?
Assume I'm willing to hack a wire into my modem/router.

If so, it might be a nice/cheap way to get a stable clock
to use with a NTP box.  (Handwave, PLLs and such.  Not a hard

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