LERG (Local Exchange Routing Guide) is a database which defines inter-exchange call routing in the North American Public Switched Telephone Network. It associates NPA/NXX's with their appropriate network elements.
Relevant NENA Documents
Note: To find and download the document, copy the document number (like NENA-STA-010) from below and search the NENA Standards and Documents page.
NENA 02-011, NENA Data Standards for Local Exchange Carriers, ALI Service Providers & 9-1-1 Jurisdictions