In general, the installation of radio equipment in a motor vehicle is permitted if the radio equipment is marked with an E-mark or a CE-mark. When installing the radio, the regulations of the vehicle manufacturer must also be observed, otherwise the general operating permit of the vehicle may expire.
Using the radio while driving is permitted, as it is not affected by the mobile phone ban. Nevertheless, the police can impose a warning fine if you show conspicuousness while driving and using the radio.
As an alternative to installing a mobile phone, you can also simply take a handheld radio into the car. We would recommend PMR, Freenet or CB handheld radios.