[asterisk-dev] Alternative Clock Source

[Tzafrir Cohen]

On Tue, Jul 10, 2007 at 02:52:32PM -0300, Paulo Garcia wrote:
> Hi All,
> 
> After some research I decided to patch the ztdummy to provide the clock
> source for Asterisk.

Please help test 

  http://bugs.digium.com/8896

It is essentially qhat you describe.

> 
> Now, I'm wondering with a scenario where I have my card and another vendor
> card (e.g. Digium or Sangoma). How the clock will work in this situation?
> The true-zaptel-card (Digium or Sangoma) will "overwrite" my patched ztdummy
> and use its own clock? Is there a way to my clock have high priority in this
> case?

The patch there also adds the option 'prefmaster' to ztdummy. This will
make ztdummy try to take the sync mastership "by force" when it loads.

However a digital span can still take timing on certain circumstnaces if
it is configured as a timing source. But then again, in setups where
you're supposed to provide timing, no other device should be a timing
source (a value other that '0' for the 'timing' parameter in the span=
line in ztcfg).

-- 
               Tzafrir Cohen       
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