Digital audio interface in a mobile telephone

Claim 1

A mobile telephone station comprising: a digital signal processor (DSP) for coding and decoding speech signals and including a codec data register; an analog codec coupled by an electrical circuit to said codec data register, for converting digital speech signals received from said codec data register in said DSP to analogue speech signals and for converting received analogue speech signals to digital speech signals and for feeding said digital speech signals to said codec data register in said DSP, said electrical circuit comprising a first circuit for coupling signals from said analog codec to said DSP and a second circuit for coupling signals from said DSP to said analog codec; and an interface circuit connected in parallel with said analog codec and to said electrical circuit, said interface circuit having inputs connected to said first circuit and second circuit and outputs connected to said first circuit and second circuit, said interface circuit including a digital audio interface block that is connectable to a system simulator and furthermore including a test access port data register coupled to said digital audio interface block and further connected to said electrical circuit between said digital audio interface block and said codec data register, whereby test data inputs and test data outputs are respectively fed to said mobile telephone station via said digital audio interface block and test access port data register from a connected system simulator, without a requirement for loading of a test program into said mobile telephone station.