A method for data communication, for coupling bus subscribers of an open automation system with distributed control, communicating with one another via a serial data bus, which interact via at least two communication controllers with a higher-level control device, in which: • each communication controller comprises at least three freely programmable communication ALU (RPA, TPA, PLA), namely the first communication ALU, the second communication ALU and the third communication ALU, • a plurality of commands are coded for each communication controller of a command code of the first and second communication ALU (RPA, TPA) of the communication ALUs, wherein the method is characterized in that for each communication controller: • logic function blocks (FI, Z, V, CRC) are arranged parallel to one another in the first and second communication ALU (RPA, TPA) and simultaneously process the command code, which carry out the communication functions, • the first communication ALU carries out the reception and decoding of a bit or nibble-oriented serial data stream and the serial/parallel conversion thereof in byte, word or double word representation, • the second communication ALU carries out the conversion of byte, word or double-word representation into bits or nibble-oriented serial data and the coding and transmission carries out this serial data stream and the third communication ALU has a monitoring logic, which simultaneously monitors a multiplicity of events and which, in the event of an event, starts within a system clock with the associated program code, wherein a plurality of commands are executed in one system clock and • the third communication ALU controls the transmission and reception profile of an associated data packet, whereby the communication functions are not permanently predefined but are formed by means of the freely programmable communication ALUs (RPA, TPA, PEA), wherein each communication controller is suitably configured by reading in an identification code in the start phase and then each associated communication ALU (RPA, TPA, PEA) and whereby transitions between networks are realized by means of the superordinate control device and each communication controller. • each communication controller comprises at least three freely programmable communication ALU (RPA, TPA, PLA), namely the first communication ALU, the second communication ALU and the third communication ALU, • a plurality of commands are coded for each communication controller of a command code of the first and second communication ALU (RPA, TPA) of the communication ALUs, wherein the method is characterized in that for each communication controller: • logic function blocks (FI, Z, V, CRC) are arranged parallel to one another in the first and second communication ALU (RPA, TPA) and simultaneously process the command code, which carry out the communication functions, • the first communication ALU carries out the reception and decoding of a bit or nibble-oriented serial data stream and the serial/parallel conversion thereof in byte, word or double word representation, • the second communication ALU carries out the conversion of byte, word or double-word representation into bits or nibble-oriented serial data and the coding and transmission carries out this serial data stream and the third communication ALU has a monitoring logic, which simultaneously monitors a multiplicity of events and which, in the event of an event, starts within a system clock with the associated program code, wherein a plurality of commands are executed in one system clock and • the third communication ALU controls the transmission and reception profile of an associated data packet, whereby the communication functions are not permanently predefined but are formed by means of the freely programmable communication ALUs (RPA, TPA, PEA), wherein each communication controller is suitably configured by reading in an identification code in the start phase and then each associated communication ALU (RPA, TPA, PEA) and whereby transitions between networks are realized by means of the superordinate control device and each communication controller.