Abstract An IC card reader/writer includes a control unit incorporating a central processing unit, read only memory, and random access memory. In addition, the reader/writer includes a UART, a sending circuit for modulating a digital signal received from the UART, transmitting and receiving antennas, and a receiving circuit for demodulating received signals. The control unit controls the IC card reader/writer by setting an interval between a trigger signal and a start flag at the time of data transmission equal in duration to at least one frame of data, for example, eight bits of data. In a specific embodiment, the trigger signal may be followed by eight bits of 00 H , followed by a start flag and eight bits of data 5A H , followed by a data stream including desired information.
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna for transmitting the send electrical signal as a radio wave; a receiving antenna for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; and a control unit for controlling said card reader/writer and for setting an interval between a trigger signal and a start flag to at least one frame.
Claim 2
Dependent Claim
112 words
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna for transmitting the send electrical signal as a radio wave; a receiving antenna for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; and a control unit for controlling said card reader/writer and for setting an interval between a trigger signal and a start flag to at least one frame.
Claim 3
Dependent Claim
22 words
The card reader/writer according to claim 1, wherein the control unit inserts dummy data between said trigger signal and the start flag.
Claim 4
Dependent Claim
16 words
The card reader/writer according to claim 2, wherein said transmitting antenna is a series resonance circuit.
Claim 5
Dependent Claim
26 words
The card reader/writer according to claim 3, further comprising a switching circuit connected between said receiving antenna and said receive circuit for disconnecting them during transmission.
Claim 6
Dependent Claim
33 words
The card reader/writer according to claim 4, wherein said switching circuit disconnects said receiving antenna and said receive circuit with a timing, that prevents switching noise from being transmitted to said receive circuit.