[Asterisk-Users] T1 Sync clarification

[dpobanz at hastingsutilities.com]

Quoting "C. Maj" <cmaj at freedomcorpse.info>: 
 
> On Sun, 11 Jan 2004,  John Brown (CV) waxed: 
>  
> > THank you.  Thats what I thought it should be. 
> >  
> > Off to call the telco and tell them they are mucked up. 
>  
> I'm wondering if I should do the same for my T400, as I seem 
> to be getting similar errors.  Might not be just the telco. 
> I set one span to 1, to sync off the telco, and the second 
> to 0, since the clock is already set by the first span.  The 
> other 2 spans are channel banks with sync set to 0. 
>  
> Does anyone else have 2 t1's plugged into their T400 ?  If 
> so, how are they synced ?  This was just happening at night, 
> but I lost the second span a dozen times already today, all 
> within less than an hour earlier this afternoon. 
 
I have 3 T1's plugged into my T400P, 1 to the telco and 2 to channel banks.  
 
Basically a T400 has one clock. This clock will free run (internal clock) if 
you have not told it to get timing from one of the incoming spans. Otherwise 
it will set the clock to the incoming T1 line which has a sync of '1'. Should 
this T1 be unavailable, the clock will be derived from the T1 with a sync of 
'2'. If both 1 and 2 are not available then it will derive the timing from 3. 
Again if the first 3 sync sorces are not available, it will look at 4.  
 
Note that at any one time only 1 of the 4 T1s can be used for a clock.  
 
Now, it is possible for you to have two telco T1's which do not have the same 
timing. This is not real likely but possible. Should this happen, there is no 
way to sync with both T1s at the same time. Only your telco could fix this.  
 
-- 
Don Pobanz 
 
>  
> Thanks, 
> --Chris 
>  
>  
> --  
>  
> Chris Maj <cmaj_hat_freedomcorpse_hot_info> 
> Pronunciation Guide:  Maj == May 
> Fingerprint: 43D6 799C F6CF F920 6623  DC85 C8A3 CFFE F0DE C146 
>  
 

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