The mobile subscriber unit (MSU) is a network component in cellular networks. It consists of the handset and the transceiver, which ensures radio transmission to the radio cells and radio reception. In cell phones, both components are integrated in the handset.
Mobile Subscriber Units (MSU) are divided into performance classes depending on the area of application. For example, a transmission power of 4 W applies to mobile subscriber units that are housed in the trunk of a vehicle and whose handset is located with the driver. In contrast, a transmission power of 1.6 W applies to portable mobile units.