The INTERBUS was developed by the company Phoenix Contact. The specification has been popular since 1987, and INTERBUS components are available from over 200 manufacturers. INTERBUS is a fast, universal and open sensor/actuator bus system with one master and several slaves. Data transmission rate and expansion of the bus are independent of one another. The gross data transmission rate is 500kBit/s, the net data transmission rate is 300kBit/s. For special applications with fiber-optic cable data transmission rates of 2Mbit/s are possible. The number of users is limited to 512.