ATIS 1000628.a.2001(S2020)

This addendum to ATIS-1000628.2000(R2005) specifies the use of the Connection Hold network capability by the Emergency Calling Service (ECS) to support ECS call hold and ring back. This addendum also specifies the TCAP messages exchanged between a switching node routing ECS calls and a Selective Routing Database (SRDB) that contains information determining the PSAP that should receive the emergency calls originating from a given caller or calling location. Formerly known as T1.628a-2001(R2005).