[Asterisk-Users] T1 Sync clarification

[Steve Underwood]

Rich Adamson wrote:

>>>What are the practical effects with in-correct clock sync
>>>-like to you hear odd buzzing, or dropped voice or gaps of audio ??
>>>      
>>>
>>You may get gaps where frames are discarded, this will be across all timeslots 
>>so an individual loss isnt a lot of data, you'll probably get away with the odd 
>>one but if you get too many and the T1 realigns it could restart and you could 
>>see the whole T1 go down and up..
>>
>>Not sure how this works in the US with such diversity available but in the UK 
>>telcos generally derive sync from another one so most of them are on the same 
>>clock source..
>>    
>>
>
>It's the same in the US, however in the US there are far more independent
>telcos (example, Iowa had the distinction of the most independent telcos 
>at 600+ of all states) and many of those do not have an engineering staff 
>nor the expertise to address this. Their engineering is typically farmed 
>out to either the central office switch vendor or to independent engineering 
>firm(s) when needed. Those groups should have addressed it, but in at least 
>some cases it was not. 
>
>The US also has some carriers that got into the national and/or international
>long distance business with a low budget staff that ran hard but never
>documented anything. (I've done some consulting work for two of those and
>wouldn't bet a dollar on their attention to detail.)
>
>Rich
>  
>
If they have frame slips too often FAX will not work. It would be hard 
for even the most incompetant telco to ignore that. However, their core 
equipment is likely to use a rhubidium clock and keep everything OK, 
even if they done sync to their peers properly.

Regards,
Steve