[Asterisk-Dev] Question about E1 Card / ISDN PRI

[Vinod Sankar]

I have a few basic questions. Apologies in advance if this is
the wrong forum for what should be a Digium FAQ.

I'm trying to use the Digium E1 card to provide an IP PBX like 
application to an enterprise that needs about 30 telephone lines, 
in India. India supports R2MF and ISDN PRI (Euro ISDN) signaling
standards. The Digium card supports only ISDN PRI. 

The questions are, 

	- Are ISDN PRI lines used only for branch to branch 
(closed group) calling, where the PSTN is unaware of how the 
channels are used (Voice/Data) or can PSTN switches terminate 
voice calls from public analog phones into this ISDN PRI circuit ?

	- The Zaptel configuration mentions framing options for defining
spans for E1 lines as either CCS or CAS. Do I specify CCS for an
E1 ISDN PRI line from PSTN terminating on this card ?

	- What interface does Digium E1 card support S/T or U ?

Also, quickly, what is the difference between R2MF and ISDN PRI ?
If someone could point me to a website that has more info on these
subjects, that would be great.

thanks,
Vinod Sankar