kamailio/utils/pdbt/docs/data_format.txt

* File format off the number portability data *

The number portability data consists only from the number or number block in
the internation format followed by an semi-colon and the carrier identity.
Each entry must be in a separate line.

Format [0-9]{n,m}; [0-9][0-9][0-9]

For example: 

495041748;012
493687413;009

The meaning of this entry is that the first number or block 495041748 belongs
to the carrier 12, the second to the carrier 9.


* File format of the carrier name file *

Each carrier id and name must be in a separate line.

Format: D[0-9][0-9][0-9] <name>

For example:

D001 Deutsche Telekom AG, Bonn
D012 BT Germany GmbH & Co. OHG

This means that the 495041748 block belongs to British Telecom Germany.