Patent ID: 9374176
Filing Date: 2016-06-21
CPC Classification: G06K,G06Q,G07F,H04B

Claim Text:
1. A point-of-sale system, comprising: a portable computing device comprising an audio jack coupled to an audio input channel, an automatic gain control (AGC) sub-circuit associated with the audio input channel, a signal processing system for processing audio signals on the audio input channel to produce digital data signals, a processor coupled to the signal processing system for receiving the digital data signals, and a payment processing application; and a card reader coupled to the portable computing device, the card reader being configured to enable a financial transaction between a customer and a merchant via the portable computing device via the payment processing application, wherein the card reader comprises: wherein the payment processing application is configured to cause the processor to initiate the financial transaction in response to receiving the digital data signals, wherein the charge pump is coupled to the audio output channel so as to cause audio noise signal in the audio output channel that is propagated to the audio input channel of the portable computing device, and wherein the audio noise signal is configured to establish a first gain amount at the AGC sub-circuit that is lower than a second gain amount required for amplifying other audio noise signals present in the audio input channel into audio signals that can be processed into digital data signals by the signal processing system.