Abstract: The object of the disclosure is an arrangement for adapting the signal level in mobile phones according to the related auxiliary device connected to the mobile phone. The microprocessor (MCU) of the mobile phone receives the connection data from the auxiliary device when the auxiliary device is connected to the mobile phone. In addition, the microprocessor comprises a memory in which the amplification data respectively required has been stored depending on the type of the auxiliary device. On the basis of this the microprocessor transmits the appropriate amplification data to the PCM-codec of the mobile phone and to its digital signal processor (DSP). Numerous auxiliary devices are viable, such as hands-free units, modems, telefaxes etc.