Communication apparatus having a SIM interface compatible with radio isolation

A method of operating a communication apparatus including a radio frequency (RF) circuit, a digital processing circuit, and an interface circuit configured to communicate with an authentication device, the method comprising:

• operating the digital processing circuit during an inactive mode of operation of the RF circuit;
• disabling at least a portion of the digital processing circuit during an active mode of operation of the RF circuit;
• and
• buffering data within the interface circuit for communication between the digital processing circuit and the authentication device during the active mode of operation of the RF circuit.

A mobile phone comprising:

• a radio frequency (RF) transceiver configured to operate on a radio frequency signal;
• a digital processing circuit coupled to the RF transceiver;
• and
• an interface circuit configured to buffer data communicated between the digital processing circuit and a secure storage device during an active mode of operation of the RF transceiver;
• wherein the digital processing circuit includes a processing unit configured to process authentication data received from the secure storage device;
• wherein the processing unit is disabled during the active mode of operation of the RF transceiver;
• and
• wherein the RF transceiver, the digital processing circuit, and the interface circuit are fabricated on a single integrated circuit chip.