Identifies the provider service center.
NOTE 1: The ICSC code appearing in this field will represent the Access Service Coordination - Exchange Company (ASC-EC) when the ASC-EC field is populated.
NOTE 2: The first two characters identify the provider. The third and fourth characters are a unique number within the region identifying the specific ICSC. The allowable range is 00 to 99. The provider will supply and periodically update the ICSC codes listing to the customer. The provider will also supply guidelines for choosing the appropriate ICSC.
NOTE 3: The format and structure of this field is defined by Telcordia in BR-751-100-801 Interexchange Customer Service Center/Service Center (ICSC/SC).
VALID ENTRIES:
Valid ICSC Code
NOTE 1: When the ASC-EC field is populated, this field must be identical to the ASC-EC entry.
USAGE: This field is required.
DATA CHARACTERISTICS: 4 alpha/numeric characters
EXAMPLE: P T 0 2