Development of model MT151 mobile access{sup}TM phone

摘要

The Model MT151 Mobile Access(tm) phone is a cellular telephone incorporating software and hardware that provides access to a variety of Internet services while maintaining the lightweight portability demanded of handheld mobile phones. ThisMobile Access phone implements these capabilities using Cellular Digital Packet Data (CDPD) wireless packet data communications technology and Unwired Planet's UP.Link application technology.Mitsubishi Hectric's Mobile Access phone adds CDPD functions and the UP.browser to the standard cellular telephone functions of the United States' Advanced Mobile Phone Service (AMPS). The stand-alone unit can send and receive email and use variousInternet services without connecting a personal computer. Because the applications and processing are performed on a web server, the system is highly flexible, allowing corporations to deliver custom user application services over private intranets. TheUP.browser functions are tightly integrated with the cellular phone functions, allowing users to dial any telephone numbers appearing on a web page without using the keypad. To protect data privacy, CDPD and UP.Link incorporate encryption andauthentication functions that operate transparently, without user intervention.The photograph in Fig. 1 shows the Mobile Access phone. The unit features an LCD screen displaying four lines of 12 characters, a 24-key keypad with integral touch-tone pad, as well as antenna, microphone, speaker and battery pack. On the side of the unit is a serial connector for attaching a personal computer and on the bottom a connector for the cigarette lighter socket in a car or other accessories.At the heart of the phone is a Mitsubishi 16-bit microprocessor, type MS 7702. Programs are stored in flash memory to allow updating. The processor runs a multitasking operating system with realtime control capabilities. Software execution is managed by a realtime monitor.