Display toll free number

Hi, I need advice on the following:-

Caller call a US toll free number and from the toll free gateway to the asterisk via PRI line.

Our requirement is we wanted the Asterisk to capture the US toll free number as DNIS and relay it to a call center agent.

The problem is, We couldn’t capture the tollfree number. All Asterisk can see is possibly the caller number all the PRI number.

Plz… Advice me… TQ

if by PRI number you mean the real number of the PRI that the tollfree is forwarded to…
then get a few PRI numbers (DIDs). Have each tollfree go to ONE PRI number. Then rewrite your callerid