# Sequence diagrams

This topic describes the exchange of commands and events between the network, SIP stack, NaturalAccess, and the application during various NCC API call control operations. The following function sequences are illustrated:

- Inbound calls

- Outbound calls

- Local disconnect

- Remote disconnect

## Inbound calls

The following illustration shows the function sequence for answering an inbound call.

## Outbound calls

The following illustration shows the function sequence for placing an outbound call:

## Local disconnect

The following illustration shows the command and event interchange for an application-initiated call release:

## Remote disconnect

The following illustration shows the command and event interchange for a network-initiated call release: