In all North American jurisdictions, special legislation permits emergency operators to obtain a 9-1-1 caller's telephone number and location information. This information is gathered by mapping the calling phone number to an address in a database. This database function is known as Automatic Location Identification (ALI). The database is generally maintained by the local telephone company, under a contract with the PSAP. Each telephone company has its standards for the formatting of the database. Most ALI databases have a companion database known as the MSAG, Master Street Address Guide. The MSAG describes address elements including the exact spellings of street names, and street number ranges.