System for influencing safety-relevant machine functions of an agricultural machine, comprising at least one electrically and/or pneumatically and/or hydraulically operated actuator for carrying out the safety-relevant machine function, further comprising a control device which is configured for indirect or direct control of the actuator, wherein the control device can be connected to at least one mobile terminal via at least a first communication channel and a second communication channel for transmitting a first signal via the first communication channel and a second signal via the second communication channel, wherein the first communication channel and the second communication channel are configured differently and are connected in parallel between the mobile terminal and the control device, wherein the at least one mobile terminal is configured for command input for influencing the safety-relevant machine function into the control device, wherein the control device is configured to perform a signal comparison of the first signal, which was transmitted by the mobile terminal via the first communication channel, and of the second signal, which was transmitted by the mobile terminal via the second communication channel, as a function of a command input effected by means of the mobile terminal and as a function of the safety-relevant machine function, wherein the signal comparison is carried out by the control device by means of a computer unit forming part of the control device and/or by means of another signal comparison unit, and desired specifications for the first signal of the first communication channel and the second signal of the second communication channel are stored in the computer unit and/or in the signal comparison unit, and wherein the control device is also configured to vary and/or activate or deactivate a safety-relevant machine function as a function of the signals determined by the signal comparison, insofar as the first signal and the second signal match the desired specifications, and whereby a signal comparison only takes place for safety-relevant machine functions. wherein the control device can be connected to at least one mobile terminal via at least a first communication channel and a second communication channel for transmitting a first signal via the first communication channel and a second signal via the second communication channel, wherein the first communication channel and the second communication channel are configured differently and are connected in parallel between the mobile terminal and the control device, wherein the at least one mobile terminal is configured for command input for influencing the safety-relevant machine function into the control device, wherein the control device is configured to perform a signal comparison of the first signal, which was transmitted by the mobile terminal via the first communication channel, and of the second signal, which was transmitted by the mobile terminal via the second communication channel, as a function of a command input effected by means of the mobile terminal and as a function of the safety-relevant machine function, wherein the signal comparison is carried out by the control device by means of a computer unit forming part of the control device and/or by means of another signal comparison unit, and desired specifications for the first signal of the first communication channel and the second signal of the second communication channel are stored in the computer unit and/or in the signal comparison unit, and wherein the control device is also configured to vary and/or activate or deactivate a safety-relevant machine function as a function of the signals determined by the signal comparison, insofar as the first signal and the second signal match the desired specifications, and whereby a signal comparison only takes place for safety-relevant machine functions.