Hi,The NI-CAN API does not expose interrupts directly. If you are using the Frame API you can use the ncWait (state=READ_AVAIL) function to wait for a new frame. If you are using the Channel API, you have to either poll for new messages/channels and check the status for the 'OldDataWarning' = 0x3FF62009, which indicates that no new data has been received yet. Alternativly, you can use the nctReadTimestamped() and set the nctPropTimeout property to wait a given amount of time.-B2k