In most cases, a two-core twisted copper cable is used. Two additional wires for earth and a 5 V power supply are optional. This is a serial, half-duplex transmission technology.
Possible transmission rates depend on the cable length. The lower the data rate, the longer the possible cable length. For example, with a data rate of 500 kbit/s, up to 100 m are possible, with 125 kbit/s up to 500 m.
Terminating resistors of 120 Ohm are required at the beginning and end of the bus line. Other possible physical transmission media are specified in ISO11898-2/3/5 and CiA303-1. Sub-D sockets/plugs, as well as screw terminals, M8 or M12 screw connectors are used as connection technology.

As a classic fieldbus, CAN follows the line topology. Stub lines should be avoided wherever possible. CAN works with a producer/consumer system or broadcast system.
The data transmission rate is either detected automatically by the CAN participants or must be set on the device or via software so that it is identical for all participants in the network.
Bus access takes place via arbitration. Each participant monitors the bus at the beginning of the transmission. If another participant transmits at the same time, the dominant bit at the beginning of a message overwrites the recessive bit of the other participant. The sender of the overwritten message recognizes this and aborts the transmission in order to try again later.

The synchronization of all participants, e.g. for arbitration, begins when the first dominant or recessive bit is received.
Synchronization is maintained by bit stuffing within the CAN message. After five bits of the same polarity, a bit with reversed polarity is inserted. The CAN transceivers of the receivers resolve this accordingly.

Messages are sent by participants on the bus, all participants receive them and use the object identifier to decide whether the message is also relevant for them according to their configuration or not. The priority on the bus is determined by the object identifier; the lower the identifier, the higher the priority.

There are two different standards for identifiers:
The basic format uses 11-bit for message identification (CAN 2.0A)
The extended format with 29-bit identifier length (CAN 2.0B)

The user data length within a message is 0-64 bits, i.e. up to a maximum of 8 bytes per message.