# Capability mask

SIP supports the nccQueryCapability function call. The capability mask indicates support of the following capabilities:

- NCC_CAP_ACCEPT_CALL

- NCC_CAP_EXTENDED_CALL_STATUS

- NCC_CAP_SEND_LINE_MESSAGE

- NCC_CAP_DISCONNECT_IN_ANY_STATE

- NCC_CAP_CALLER_ID

- NCC_CAP_REGISTER_USER

- NCC_CAP_ACKNOWLEDGE_CALL

Refer to the NCC Service Developer's Reference Manual for information about the first five mnemonic capabilities in the previous list. The SIP-specific mnemonic capabilities are described in the following table:

Mnemonic | If the bit is set...
NCC_CAP_REGISTER_USER | The SIP stack is capable of registering a user with a SIP registrar. For more information, refer to Registering a user.
NCC_CAP_ACKNOWLEDGE_CALL | The NCC API call nccAcknowledgeCall is enabled. For more information, refer to Acknowledging a call.