1. A system for providing selective reconfiguration in a multiple application personal communications device, comprising: a data storage in the device, for storing program instructions; a bus means in the device, coupled to said data storage; a data processor in the device, coupled to said data storage over said bus means, for executing said stored program instructions; a multiplexer means coupled to the data processor, for selectively interconnecting signal lines connected thereto, in response to control signals from the data processor; a voice transducer means coupled to said multiplexer means; a program means stored in the data storage, having a first portion for managing communications using a public switched telephone network; said program means having a second portion, for managing communications using a mobile radio telephone network; a decoding means coupled to the data processor and to the data storage, for selectively causing either said first portion or said second portion of said program means to be executed by the data processor; an option connector receptacle coupled to said decoding means; a first option attach connector having a terminal coupled to said public switched telephone network, for selective connection to said option connector receptacle; said terminal of said first option attach connector being coupled to said multiplexer means; a first connector identification means included with said first option attach connector, for identifying said first option attach connector to said decoding means when said first connector is connected to said receptacle, and in response thereto, said decoding means causing the execution of said first portion of said program means; said first connector identification means included with said first option attach connector, identifying said first option attach connector to said decoding means when said first connector is connected to said receptacle, and in response thereto, said decoding means causing said data processor to signal said multiplexer to couple said public switched telephone network to said voice transducer means; said decoding means causing said second portion of said program means to be executed when said first connector is not connected to said receptacle.