Electrical or electronic measuring transmitters, especially for measuring a physical, chemical, or analytical parameter; amperometric sensors, especially digital amperometric sensors; amperometric transmitters, especially digital amperometric transmitters; potentiometric sensors, especially digital potentiometric sensors; potentiometric transmitters, especially digital potentiometric transmitters; digital sensors comprising a plug connector with inductive coupling for the transmission of measured data; plug connectors with galvanic isolation and inductive coupling; connector head, threaded plug connector head; connector plug for an electrode, said plug connector comprising a memory module containing sensor data, calibration data, and electronic signatures; connector cables for galvanically isolated connection between sensors and analysing instruments, such as pH-transmitters, personal computers, for measuring pH, or other electrotechnical potentials, or amperometric signals by means of digitized analog signals; accessories for electronic measuring transmitters or sensors, especially accessories for electronic measuring transmitters or sensors with galvanically isolated interfaces, namely operating devices, display devices, test apparatuses, data simulating apparatuses, data acquisition apparatuses, data reading apparatuses, data recording apparatuses; photovoltaic solar collector modules for generating electrical power, battery modules, data transmitter and/or receiver modules for transfer of measured data from sensors and transmitters, respectively, apparatuses for maintenance and calibration of sensors; software for operating, bringing into service, setting parameters, testing, maintenance, calibration, or management of measuring transmitters and sensors, respectively; all of the above goods only in the fields of industrial process measurement instrumentation; industrial process automation; laboratory measurement instrumentation; laboratory automation; manufacturing automation; building automation; enviromental measurement instrumentation; medical technology; and traffic engineering; none of the above goods in the fields of office technology and office equipment, respectively