The LERG/LCADS Routing Guides are key to finding the best and cheapest routes for service providers such as wireless, mini-telecoms and wholesale providers such as calling card providers
The Local Calling Area Data Source (LCADS) is a database containing calling area information inside the United States and Canada. LCADS is the premeir tool for mapping NPA NXXs to geographical locations and distinct local billing zones
The Local Exchange Routing Guide (LERG) contains the following information:
More Information on LNP (Local Number Portability): In 1996, the US Congress mandated a change in local telephone service that allows any carrier to enter a local market. The new regulation provides for Local Number Portability (LNP), which means that when a consumer's phone service is moved from one service provider to another, the telephone number (TN) does not change.