A data processing and transmission system adapted to be operatively interposed between a numerical control unit for a machine tool and devices present in the machine tool, comprising: - at least one input channel adapted to a transit of operational signals from or to said devices present in the machine tool; - electronic circuits configured to process said operational signals to make available on an output interface control signals for the numerical control unit, - a multipolar cable having a first and a second end, each provided with a multipolar connector; - a master unit having the output interface, a main processor, a memory and at least one socket configured to be coupled to one of the multipolar connectors; - a plurality of slave units, each provided with at least one external port defining said input channel, a memory, a secondary processor, and provided also with a first socket and a second socket, configured to be coupled at least to a first or a second connector of the multipolar connectors in order to interconnect the slave unit at least with the master unit, the slave units being connected in series to each other and to the master unit in a 'daisy chain' configuration, one of the slave units being connected to the master unit by means of a piece of the multipolar cable, wherein the master unit has a clock and each slave unit has its own clock, and wherein the main processor is programmed to divide a data transmission time interval into a plurality of time slots and to uniquely assign to each slave unit a corresponding time slot of said plurality of time slots, and wherein, for each slave unit, the secondary processor is configured to be set to transmit data through the multipolar cable only within the respective time slot, the main processor being further programmed to generate a synchronization signal and to transmit said synchronization signal through the multipolar cable in order to synchronize all the clocks of the slave units with the clock of the master unit, each slave unit receiving the synchronization signal as it is generated by the master unit and synchronizing its own clock independently from the other slave units, the cable comprising at least a first bundle of signal wires, intended for a corresponding communication channel between the master unit and the slave units, and one or more power wires for distributing electrical power supply in the system. - at least one input channel adapted to a transit of operational signals from or to said devices present in the machine tool; - electronic circuits configured to process said operational signals to make available on an output interface control signals for the numerical control unit, - a multipolar cable having a first and a second end, each provided with a multipolar connector; - a master unit having the output interface, a main processor, a memory and at least one socket configured to be coupled to one of the multipolar connectors; - a plurality of slave units, each provided with at least one external port defining said input channel, a memory, a secondary processor, and provided also with a first socket and a second socket, configured to be coupled at least to a first or a second connector of the multipolar connectors in order to interconnect the slave unit at least with the master unit, the slave units being connected in series to each other and to the master unit in a 'daisy chain' configuration, one of the slave units being connected to the master unit by means of a piece of the multipolar cable, wherein the master unit has a clock and each slave unit has its own clock, and wherein the main processor is programmed to divide a data transmission time interval into a plurality of time slots and to uniquely assign to each slave unit a corresponding time slot of said plurality of time slots, and wherein, for each slave unit, the secondary processor is configured to be set to transmit data through the multipolar cable only within the respective time slot, the main processor being further programmed to generate a synchronization signal and to transmit said synchronization signal through the multipolar cable in order to synchronize all the clocks of the slave units with the clock of the master unit, each slave unit receiving the synchronization signal as it is generated by the master unit and synchronizing its own clock independently from the other slave units, the cable comprising at least a first bundle of signal wires, intended for a corresponding communication channel between the master unit and the slave units, and one or more power wires for distributing electrical power supply in the system.