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CG-EWCG-001 Wireless E911 Guide
Issue 3, January 6, 2004 TN Database Updates
5. TN Database Updates
5.1 Overview
The E911 Telephone Number (TN) database contains data records provided by the different wireline and
wireless carriers offering service within the E911 service area. For wireline service, the TN records
contain the subscriber’s telephone number, name, service address, and other information about the fixed
wireline subscriber location that may be helpful in providing emergency response. Wireless data must
be treated differently due to the nature of the service and the mobility of the caller’s location. Individual
wireless subscriber information is not entered into the E911 TN database unless the service is provided to
a fixed location.
Phase 1 of FCC Docket 94-102 requires Wireless Carriers to provide the cell site sector location
information and call back number for each 911 call to allow the PSAP to have a general idea of where the
call originated and enable them to call the person back in the event the call is disconnected. Phase 2 of the
FCC Docket requires Wireless Carriers to additionally provide the latitude and longitude coordinates of the
caller’s location. There are various technological solutions available for Wireless Carriers to meet these
Phase 1 and 2 requirements.
Some solutions require that the TN data records provided by the Wireless Carriers define cell site sector
location information of the geographical area from where the 911 call originated. This is normally done
by creating TN records that represent each face of each antenna. These records must contain an MSAG
valid address of the antenna structure and contain cell site sector location information that will help the
PSAP in locating the general vicinity of the 911 caller. These data records are assigned numbers by the
Wireless Carrier, sometimes referred to as Pseudo-ANI or pANI numbers. Some technological solutions
require pANI numbers to be assigned to each antenna face while other solutions require pANI numbers to
be assigned to each PSAP. In either case, the database records originally provided by the Wireless Carriers
must contain MSAG valid addresses. Multiple pANI numbers per antenna face or PSAP may also be
required to handle concurrent 911 calls from the same antenna face. Wireless Carriers must determine the
E911 database impact and requirements for the technological solution implemented.
The ten digit call back number of the wireless caller and the latitude/longitude coordinates are normally
provided to the full featured E911 database by way of a real time update during 911 call processing. This
interface to the E911 database will vary by the technological solution implemented, but normally involves
updating the corresponding TN database pANI record to include the ten digit call back number of the
caller, latitude/longitude, and in some solutions, the cell site sector location information. Concurrent 911
calls processed by the same antenna face may require multiple pANI numbers and database records to be
assigned. As the PSAP receives the 911 call and pANI from the Wireless Carrier, the real time update
takes place and stores the caller’s call back number and latitude/longitude in the TN database pANI
record. The PSAP equipment will query the E911 database using the number provided with the call. The
Automatic Location Identification (ALI) returned to the PSAP will include the cell site sector location
information, latitude/longitude, and the caller’s ten digit call back number. Premises based ALI systems
may not support pANI database records or a real time update interface. Wireless Carriers should identify
premises based ALI systems in their service area and explain the impact to the E911 Customers.
In most cases a Wireless Carrier will offer service in areas already converted to Enhanced 911. All
pseudo-ANI TN records must be initially loaded into the E911 database and updated on an ongoing daily
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