DNIS
A related service feature available to Inward WATS subscribers is the Dialed Number Identification Service (DNIS), a code related to the number that the caller dialed when accessing the WATS line. With the information, the service provider can have several toll-free numbers directed to the same call center and provide unique service based on the number dialed. DNIS can also be used to identify other call routing information. For example, the WATS service can be configured to send a specific DNIS number that is assigned to callers from geographic regions based on city, area code, state, or country.
Read more about this topic: Automatic Number Identification