Not sure what PRA is.
In (very) rought terms, think of PRI like a T1 line cut into 24 64K channels.
Use one of them as a D channel and you get 23 B channels.
Now, you are in Europe, so you're PRI is based on E1. Take an E1 and cut
it into 32 64K channels - lose ont for D channel, one for another signalling
thing I've forgotten the name of, and then you have 30 B channels.
In the US, channelized T1 is a T1 cut into 24 64K channels. Now, there is
NO ISDN ability, and the signalling is inband. So you lose 8K per channel
to signalling. Leaving you with 24 channels with 56K useful for data.
In Europe you have channelized E1. Take an E1, cut into 32 channels.
The signalling is OUT of band, using, again, 2 channels. NO ISDN again.
So now you have, again, 30 channels with 64K useful for data.
-MZ
-- Livingston Enterprises - Chair, Department of Interstitial Affairs Phone: 800-458-9966 510-426-0770 FAX: 510-426-8951 megazone@livingston.com For support requests: support@livingston.com <http://www.livingston.com/> Snail mail: 4464 Willow Road, Pleasanton, CA 94588