The hardware at a CAN node can be in one of three states, depending upon the number of errors detected and counted by its internal transmit and receiver error counters, TEC and REC. The Error Active State is the normal operating mode for the hardware. Messages can be received and transmitted. When the node detects an error, it sends and active error flag. The hardware enters the Error Passive State when it has counted more than 127 transmitting or receiving errors. Messages can still be received and transmitted in this state. When a node detects an error while receiving in Error Passive State, it sends a passive error flag (6 recessive bits). The hardware enters the Bus-Off State if it has had serious problems transmitting messages and the accumulation of problems caused the Transmit Error Counter to reach its maximum count of 255. Basically, the node is turned off and cannot receive or transmit messages until the host processor resets it or until it receives 128 occurrences of 11 consecutive recessive bits (a bus recovery sequence). This fault containment method prevents a faulty node from continuously transmitting and thereby effectively shutting down all communication on the network. Depending on the network rules, nodes participate in frame verification if they are Error Active. If not, they have become Error Passive or enter Bus-Off States.