text message for transmission over a communication network and device resident functions such as a calculator or task list operating system software 54 and various software applications 58 used by the microprocessor 38 are in one example embodiment stored in a persistent store such as flash memory 24 or similar storage element those skilled in the art will appreciate that the operating system 54 specific device applications 58 or parts thereof may be temporarily loaded into a volatile store such as ram 26 it is contemplated that received communication signals may also be stored to ram 26 the microprocessor 38 in addition to its operating system functions preferably enables execution of software applications 58 on the device a predetermined set of applications 58 which control basic device operations including at least data and voice communication applications for example will normally be installed on the device 10 during manufacture further applications may also be loaded onto the device 10 through the network 50 an auxiliary i o subsystem 28 serial port 30 short range communications subsystem 40 or any other suitable subsystem 42 and installed by a user in the ram 26 or a non volatile store for execution by the microprocessor 38 such flexibility in application installation increases the functionality of the device and may provide enhanced on device functions communication related functions or both for example secure communication.