Abstract: In one embodiment, a card reader device includes: circuitry having exactly three non-wire elements of (a) one two-terminal inductive read head having a first read head terminal and a second read head terminal, (b) one two-terminal resistor having a first resistor terminal and a second resistor terminal, and (c) one TRS (tip, ring, sleeve) connector including a microphone contact and a circuit completion contact, with said TRS connector adapted to be inserted into a socket of a cell phone to connect the microphone contact and circuit completion contact to corresponding cell phone circuitry including connecting to a microphone input of the cell phone; wherein said three non-wire elements are connected together using one or more direct connections, one or more wires, or both; and a housing enclosing said read head and said resistor, with said TRS connector extending out of the housing.

Abstract: In one embodiment, a card reader device includes: a read head configured to produce a signal indicative of data stored on a magnetic stripe of a card in response to the magnetic stripe being passed by the read head; means for passively attenuating configured to attenuate the signal indicative of data stored on the magnetic stripe resulting in an attenuated output signal indicative of said data stored on the magnetic stripe; and a tip, ring(s), sleeve output plug adapted to be inserted into a standard headset jack associated with means for communicating with a host system and configured to provide the attenuated output signal indicative of said data stored on the magnetic stripe to the communicating means via a microphone input of the standard headset jack. The means for communicating with a host system and/or host system perform processing based on the attenuated output signal.

Abstract: In one embodiment, a card reader device includes: a read head configured to generate a signal indicative of data stored on a magnetic stripe of a card, an output plug, adapted to be inserted into a headset jack of a mobile host device, configured to communicate an output signal indicative of data stored on the magnetic stripe to a microphone input of the headset jack of the mobile host device; and circuitry configured to set the amplitude, which includes attenuation by at least a resistor, of a signal communicating said data included in the signal indicative of data stored on the magnetic stripe generated by the read head resulting in the output signal indicative of data stored on the magnetic stripe. In one embodiment, the circuitry includes decoding circuitry configured to decode the signal indicative of the data stored on the magnetic stripe.