The advance of mobile network and radio techniques has been rapidly expanding the service area for mobile terminals. Thus, mobile communications have been devoted to the improvement of terminal mobility (TM). Recently, the personal mobility (PM) concept appeared which gives a freedom to use personal telecommunication numbers at any terminal. Therefore, mobile network must next enable a user to access telecommunication services with his/her personal telecommunication number from any terminal at any geographic location. In other words, the mobile network must implement universal mobility (UM) that integrates TM and PM. This paper first provides a definition of UM. Next, it describes the identity and number configurations for UM and then presents network techniques for UM, i.e., the network architecture and UM management procedures. It also presents the current status of standardization on UM in the Personal Digital Cellular system (PDC) and Future Public Land Mobile Telecommunication Systems (FPLMTS).