Communication system for transmitting information via drilling rod linkages (3, 4, 5, 6, 8, 9, 10, 80) of a drilling string for earth drillings, comprising a first drilling rod linkage (8, 80), one or more second drilling rod linkages (3, 4, 5, 6, 9, 10) and a drill drive, wherein the first drilling rod linkage (8, 80) and the second drilling rod linkage or linkages (3, 4, 5, 6, 9, 10) is/are formed in each case from a hollow-cylindrical drill pipe having at least one line (21, 22) extending in the axial direction and having an upper end and a lower end, the lower end of the first drilling rod linkage (8, 80) has a receptacle for a drill head, each of the second drilling rod linkages (3, 4, 5, 6, 9, 10) is connected in a rotationally fixed manner with its lower end to the upper end of the first drilling rod linkage (8, 80) or of another second drilling rod linkage (3, 4, 5, 6, 9, 10) and is connected in a rotationally fixed manner with its upper end to the lower end of a further second drilling rod linkage (3, 4, 5, 6, 9, 10) or to the drill drive, wherein the communication system furthermore comprises: - sensors and/or actuators from which or to which measurement, parameterizing, status and/or control data are to be transmitted and which are arranged at the lower end of the first drilling rod linkage (8, 80) and/or at the drill head, - a first communication unit and an electronics unit at the drive end, both of which are arranged at or in the drill drive and are connected to one another, - a surface computer (100, 101) for monitoring the earth drilling, which is communicatively connected to the electronics unit at the drive end and receives or provides the data of the sensors and/or actuators, - further communication units (17, 19), at least one of which is arranged at the upper end of the first drilling rod linkage (8, 80) and at least in each case one is arranged at the two ends (13, 14) of the second drilling rod linkage or linkages (3, 4, 5, 6, 9, 10), - at least one electronics unit with a microcontroller in each case in the drilling rod linkages (3, 4, 5, 6, 8, 9, 10, 80), and - at least one power supply for the communication units (17, 19) and the electronics unit in each case in the drilling rod linkages (3, 4, 5, 6, 8, 9, 10, 80), wherein the sensors and/or actuators and the communication unit of the first drilling rod linkage (8, 80) are connected to one another via its electrical line (21, 22) and the electronics unit of the first drilling rod linkage (8, 80) is located between the sensors and/or actuators and the communication unit of the first drilling rod linkage (8, 80) with respect to data, and the communication units (17, 19) of each second drilling rod linkage (3, 4, 5, 6, 9, 10) are connected to one another via its electrical line (21, 22), wherein the electronics unit of the respective second drilling rod linkage (3, 4, 5, 6, 9, 10) is located between the communication units (17, 19) with respect to data, and wherein the communication units (17, 19, 72) are radio modules and each of the communication units (17, 19, 72) is arranged for transmitting the data to the immediately adjacent communication unit (17, 19) of the next drilling rod linkage (3, 4, 5, 6, 8, 9, 10, 80) or of the drill drive and/or for receiving data from this unit, characterized in that an unambiguous identifier is allocated to each drilling rod linkage (3, 4, 5, 6, 8, 9, 10, 80) via which it is identifiable and which is stored in the electronics unit and/or in one or more of the communication units (17, 19) and can be queried by the communication unit at the drive end. - sensors and/or actuators from which or to which measurement, parameterizing, status and/or control data are to be transmitted and which are arranged at the lower end of the first drilling rod linkage (8, 80) and/or at the drill head, - a first communication unit and an electronics unit at the drive end, both of which are arranged at or in the drill drive and are connected to one another, - a surface computer (100, 101) for monitoring the earth drilling, which is communicatively connected to the electronics unit at the drive end and receives or provides the data of the sensors and/or actuators, - further communication units (17, 19), at least one of which is arranged at the upper end of the first drilling rod linkage (8, 80) and at least in each case one is arranged at the two ends (13, 14) of the second drilling rod linkage or linkages (3, 4, 5, 6, 9, 10), - at least one electronics unit with a microcontroller in each case in the drilling rod linkages (3, 4, 5, 6, 8, 9, 10, 80), and - at least one power supply for the communication units (17, 19) and the electronics unit in each case in the drilling rod linkages (3, 4, 5, 6, 8, 9, 10, 80),