Asterisk ans SIP

Hi All,

I am developing call center applications using SIP.For testing purposes i need asterisk.Uptill now i have understood that we need a digium card that will be fitted in our system to terminate PRI lines.Plz guide me on this a bit more.I am still not clear with this concept of terminating PRI lines.Which digium cards(model) are used for this purpose and how many channels can be used with one card…plz throw some light

Vibhor (although at least one is Basic Rate).

There are competing products from other suppliers.