Physical layers

Profibus implements three main physical layers to meet industrial communication requirements.

For industrial environments where electromagnetic interference is common, the RS485 standard enables communication at data rates ranging from 9.6 kbit/s to 12 Mbit/s; this is the high-speed H2 medium 5.1 . On the other hand, fiber-optic (FO) transmission is available via fiber-optic repeaters, enabling the communication medium to be extended geographically, as well as crossing areas of high electromagnetic interference. Optical stars can be used to create tree topologies.

...