| 摘要 |
When establishing an emergency call connection towards a Public Safety Answering Point (PSAP) terminal for a mobile subscriber, instead of transmitting the Mobile Station Integrated Service Directory Number (MSISDN) assigned to the mobile station, a directory number assigned to the serving mobile switching center/visitor location register (MSC/VLR) is transmitted as the Calling Party Number. The MSISDN number is stored into the Generic Address Parameter (GAP) within the transmitted Initial Address Message (IAM) signal. When the PSAP attempts to call back the mobile station in response to a disconnection of the original emergency call connection, the PSAP transmits another IAM signal with the received MSC directory number as the Called Party Number. Once the setup signal is routed to the serving MSC/VLR, an application module within the serving MSC/VLR extracts the MSISDN from the GAP to call back the proper mobile station. |
