Identifies the Exchange Carrier requesting local services.
NOTE 1: The format and structure of this field is defined in the ANSI approved standard, ATIS-0300251. Codes for Identification of Service Providers for Information Exchange.
VALID ENTRIES:
A four alpha/numeric character code structure for all Exchange Carriers in North America and certain U.S. territories maintained by NECA.
USAGE: This field is conditional.
NOTE 1: Required when ordering local interconnection services or unbundled network elements, otherwise prohibited.
DATA CHARACTERISTICS: 4 alpha/numeric characters
EXAMPLES: 8 7 1 2
1 2 A 3