Accessory interface for a portable communication device

A method for interfacing an electronic accessory to a portable radio, comprising:

• detecting that the accessory is attached to the portable radio and turned on;
• synchronizing that portable radio to the accessory;
• providing an indicator to the portable radio from a memory of the accessory via a unidirectional configuration interface that the accessory provides selectable UART/USB functionality;
• reading a status input of a single ended one (SE1) input port of a microprocessor of the accessory and determining one of:
• an invalid USB logic configuration;
• and
• a valid USB logic configuration;
• selecting a UART mode of operation when an invalid USB logic configuration is presented to the SE1 input of the accessory microprocessor;
• and
• selecting a USB mode of operation when a valid USB logic configuration is presented to the SE1 input of the accessory microprocessor.

A communication system, comprising:

• a plurality of portable communication devices having different data connectivity types;
• an electronic accessory, comprising:
• a connector providing interchangeable attachment of the accessory to each of the plurality of portable communication devices, the connector having an accessory detect pin, a first general purpose input output (GPIO1) pin, and a second general purpose input output (GPIO2) pin;
• a configuration memory indicating selectable data functionality, the configuration memory being operatively coupled to the accessory detect pin of the connector via a unidirectional configuration interface, the unidirectional configuration interface indicating the selectable data functionality to an attached portable communication device of the plurality of portable communication devices;
• a microprocessor that supports the selectable data functionality via a single ended one (SE1) input, wherein:
• an invalid signal configuration is presented by the attached portable communication device to the GPIO1 and GPIO2 pins for a first data connectivity type;
• and
• a valid signal configuration is presented by the attached portable communication device to the GPIO1 and GPIO2 pins for a second data connectivity type;
• and
• a switch responsive to the microprocessor, the switch multiplexing data connectivity signals presented by the portable communication device to the first and second GPIO pins to corresponding input pins of the microprocessor to enable accessory operation with a selected data connectivity type.