Subsequently, in 1993, the specification for the simpler and thus considerably faster protocol PROFIBUS DP (Decentralised Peripherals) was completed.

[3] To use these functions, various service levels[10] of the DP protocol[11] were defined:[12][13] The data link layer FDL (Field bus Data Link) services[15]and protocols[16] work with a hybrid access method that combines token passing with a master/slave method.

The master signals the start of a new telegram with a SYN pause of at least 33 bits (logical "1" = bus idle).

They can be differentiated by their start delimiter (SD): SD1 = 0x10 SD2 = 0x68 SD3 = 0xA2 SD4 = 0xDC Three different methods are specified for the bit-transmission layer:[9] For data transfer via sliding contacts for mobile devices or optical or radio data transmission in open spaces, products from various manufacturers can be obtained, however they do not conform to any standard.

[21] PROFIBUS PA[8] runs at fixed speed of 31.25 kbit/s via blue sheathed two core screened cable.

Profiles are important for openness, interoperability and interchangeability, so that the end user can be sure that similar equipments from different vendors perform in a standardised way.

User choice also encourages competition that drives vendors towards enhanced performance and lower costs.

There are PROFIBUS profiles for Encoders, Laboratory instruments, Intelligent pumps, Robots and Numerically Controlled machines, for example.