Patent ID: 9042845
Filing Date: 2015-05-26
Classification: H04B,H04R

Abstract:
1. A communication system, comprising: a radio; a primary accessory coupled to the radio; and a secondary accessory attached to the primary accessory, the secondary comprising a resistor network for switchably coupling parallel resistors into parallel combinations of resistors in response to a bias input generated from either a microphone bias voltage or speaker bias voltage of the primary accessory, the parallel combinations of resistors within the resistor network indicating the secondary accessory type; and a current to voltage converter for generating an analog voltage representative of the current being sourced to the resistor network of the secondary accessory; an analog-to-digital converter for generating a digitized signal of the analog voltage; control logic for sampling and averaging the digitized signal and determining the secondary accessory type based on the sampled and averaged digitized signal; a detect circuit for detecting the coupling of the secondary accessory to the primary accessory and providing a detect signal to the control logic to enable power up of the secondary accessory; and bias detect and control circuitry for receiving the bias input to control the switchably coupled resistors of the resistor network; and a first resistor coupled between an output of the current to voltage converter and a return line of the detect circuit; and a second resistor switchably coupled in parallel to the first resistor; and a third resistor switchably coupled in parallel to the second resistor, the first second and third resistors.