[Asterisk-Users] Asterisk - fax - spandsp

[Steve Underwood]

Michael Welter wrote:

>
>> What is in the bug tracker helps make things clearer to people who 
>> know what they are doing. What we need is something that makes things 
>> clear to laymen. Saying internally and externally clocked doesn't cut 
>> it. It needs to be made clear to laymen that clocking internally is 
>> rarely right; that slaving to a PBX, when there is also a PSTN 
>> connection is almost never right; that the PSTN is the grand master 
>> of the telecoms universe, and all Asterisk boxes should be its slave.
>>
>
> Maybe the confusion is because some pieces of the explanation are 
> being left out.  If you look at the leads on a synchronous RS232 
> interface it is very clear:  Rx clock and Tx clock, and people 
> understand that.  It's not as clear-cut with T1/E1.
>
> I'm not the person to explain this, but someone (Rich Adamson perhaps, 
> or a Digium engineer) needs to explain phase-locked loops and the 
> recovery of the timing signal from the data stream.  Perhaps 
> understanding that the timing comes from the data stream itself might 
> lead to better understanding.

Put the term PLL into an explanation, and 99% of the people reading will 
switch off.

Regards,
Steve