# Rejecting calls through gateway applications

When a gateway application places an outbound call in response to inbound calls on another trunk, the call may be rejected for a variety of reasons. When this happens, the application must also reject the corresponding inbound call. The following illustration shows how this process works:

The way a gateway application rejects calls is similar to the way it accepts calls. Initially, the TCP accepts the incoming call and puts it on hold by sending silence to the line. When the outbound call is rejected, the application calls nccRejectCall. The TCP immediately starts to perform the action requested by nccRejectCall. It can play a busy tone, or let the application play a reject message. The TCP then relies on the caller side to tear down the connection.