# Action code values

The following table lists the valid action code values for ACU_FACILITY_IN, ACU_SET_MODE_CO, ACU_SET_MODE_RQ, ACU_TEST_CO, and ACU_TEST_RQ messages.

These values are defined in isdnacu.h.

Action code | Description
--- | ---
ACU_RQ_ACTIVATE | Activate or register action.
ACU_RQ_CLEAR | Deactivate or clear action.
ACU_RQ_ENQUIRY | Inquiry action.
ACU_IN_TX | Transmission.
ACU_CO_ACK | Acknowledgement.
ACU_CO_REJ | Reject.