Portable computing hosts, such as PDAs, are customized for use in diverse
applications, such as media and game players, through use of a first-level removable
expansion module having player-specific circuitry and a slot for a second-level
removable module, such as a removable memory. For example, in combination with
a connected or attached user interface device (e.g., earphones), these modules
provide a host with external-interface circuitry and/or application-specific functions
as well as second-level removable memory functions. The removable memory may be
used to store and playback digitally encoded media such as music, audio, or video.
The removable memory may also be used directly or predominantly by the player's
application specific circuitry within the first-level removable expansion module.
In illustrative embodiments, an industry standard physical and electrical interface
couples the application specific module to the portable computing host, which provides
user interface functions for the application.
