Various topologies are known from network technology, such as bus topology, ring topology, tree topology and meshed topology for meshed structures. In addition, there is above all the line topology used in fieldbuses, in which the signal is looped through from consumer to consumer.
This structure differs from the ring topology, which is also used in fieldbuses, in that it is not a double ring as usual, but a single ring. It therefore consists of only one cable connection, but does not offer any redundancy in the event of a fault.
The line topology can be built up by implementing switches. It is mainly used in automotive technology and in large production facilities to connect production cells. Fieldbus systems in line topology include the CAN bus, the AS interface, EtherCAT and the Sercos interface. In addition, Single-Pair Ethernet( SPE) can be set up in star topology and also in line topology as SPE multidrop. This topology has particular advantages in automotive technology because it allows several functions to be implemented in certain areas of the vehicle via a cable connection that is looped through from consumer to consumer. This is in contrast to the star topology, in which a separate cable must be laid to the SPE switch for each function unit.