[asterisk-users] Use modprobe to find E1/T1 jumper setting onPRI card

[A J Stiles]

On Wednesday 29 Sep 2010, Lee, John (Sydney) wrote:
> Do you mean that if I could define 30 channels in span 1 for example, then
> span 1 is set to E1?
>
> If not, then it is T1.

Yes!  That's how it works.

Civilised countries manage to squeeze 30 B-channels and two D-channels onto an 
ISDN line by using trinary encoding, where three "trits" represent four bits.  
DC balancing is achieved by using two  (equal and opposite)  3-trit 
representations for each of the nybbles represented by unbalanced symbols, 
and sending one or the other depending whether the imbalance is positive or 
negative.

This gives 33% extra capacity as compared to simply sending ones as positive 
or negative in strict alternation, hence 30 + 2 aot 23 + 1.

-- 
AJS