Transaction Capabilities Application Part is a signaling protocol within the Signaling System 7 stack. It facilitates the exchange of non-circuit-related information between network nodes, such as querying databases for toll-free number routing, mobile subscriber roaming validation, and intelligent network services. It allows multiple concurrent dialogs between application entities.
Heard on the job
The call failed because the MSC couldn't establish a TCAP dialogue with the home location register to verify the subscriber.