Mobile networks provide support for routing and location management functions. Wireless networks provide wireless interfaces to users. When mobility and wireless are combined, interesting issues arise that bear on performance, interoperability, and competing standards. This chapter examines different cellular technologies, including personal communication service (PCS) and cellular digital packet data (CDPD). A PCS network is a wireless network that provides communication services to PCS subscribers. The service area of the PCS network is populated with base stations. Like a cellular network, the radio coverage of a base station is called a cell. The base station locates a subscriber or mobile unit and delivers calls to and from the mobile unit by means of paging within the cell it serves. Cellular digital packet data (CDPD) is the latest in wireless data communication and offers one of the most advanced means of wireless data transmission technology.