a block diagram of a mobile phone according to one embodiment of the invention a mobile phone 10 comprises a receiver 101 processor 103 switch 105 a screen 106 a keypad 107 a ringer 108 a connection port 109 and sim cards 1052 1055 the receiver 101 comprises a transceiver 1012 a speaker 1013 a microphone 1014 an earphones 1015 and an antenna 1016 the processor 103 comprises a cpu 1031 and a storage device 1032 having a memory 1033 storing id codes identifying the direct service providers of the sim cards 1052 1055 and a memory 1034 storing a priority table the switch 105 is a multiplexer 1051 0019 fig4 is a priority table stored in the memory 1034 in fig1 the priority table shows each fee rate under cooperation between one sim card with one compatible service provider in us cents per second when the destination of a call is determined for example the fee rate under the cooperation of the card idv with the provider t is 14 cents second please refer to fig2 together with fig1 a base station 700 of a local telecommunication service provider communicates with the mobile phone 10 through a radio signal y 4 received by the antenna 1016 the radio signal y 4 carries an id code id 4 identifying the local telecommunication service provider the cpu 1031 is connected.