BWT via PRI, inbound are DID or DNIS (4-digit). Bulk of DN range is 7xxx, but there are also 9xxx (POTS <fax lines> that were ported). AS of now the Trunk Service incoming digit mod strips 1st digit and inserts a '7'; the 7xxx route to matching 7xxx DNs on stations, the 9xxx route to other 7xxx...