It's a "dialing plan" or "dial plan", something that once occupied a useful part of my head when I was helping design telephone switching systems at Nortel Networks.

Voip.ms usually has examples of exactly what to use on any given ATA, but one can cleverly customize those further for greater convenience. Eg. to eliminate the need for the area code prefix on numbers you dial a lot, etc.

http://www.cisco.com/c/en/us/support/doc...pqa-108747.html

Cheers