ATIS 1000628A: Supplement to T1.628-2000; Formerly T1.628a-2001

Scope and purpose

This standard specifies the capabilities required to support the passing of location and callback information associated with the calling user to a Public Safety Answering Point (PSAP) attendant, to provide network routing and transfer features associated with emergency service calls, and to deliver control indications (e.g., flashing display) to the PSAP attendant. Emergency Calling Service (ECS) allows emergency service calls to be completed through the network to an appropriate emergency service attendant, and to provide the PSAP attendant with location information (if available) regarding the calling user.

ECS also provides for priority routing of the call within the network so that even in times of network congestion, emergency calls should be able to complete to a PSAP attendant. It also allows for the transport and identification of emergency service calls without the use of dedicated facilities. In addition, the network provides additional capabilities (e.g. the transfer of location information) when the attendant conferences with, or transfers the call to, any other attendant in the emergency serving area.

Capabilities needed for supporting E9-1-1 Call Hold and Ringback are described in Clauses 4 and 5. However, there is no DSS1 or SS7 support for these capabilities at this time.

Finally, this document provides for the delivery of location information to a PSAP over a DSS1 interface. In addition, receipt of location information for calls originating from a DSS1 interface is addressed. An ECS call may originate from a wireline or wireless user.

Application

This standard is intended to supplement the basic call procedures described in:

• American National Standard for Telecommunications - Signalling System no. 7 (SS7) - Integrated Services Digital Network (ISDN) user part, T1.113.

• American National Standard for Telecommunications - Integrated Services Digital Networks (ISDN) - Layer 3 Signaling Specification for Circuit Switched Bearer Services for Digital Subscriber Signaling System Number 1 (DSS1), T1.607.

ECS is applicable only to the speech and 3.1-kHz audio information transfer capabilities identified in T1.113 and T1.607.