Automatic mode detection in a dual operating mode RFID tag

A system for RFID communications comprising an interrogator and a transponder that responds to one of a first or second interogator communication protocol as a dominant protocol and the other of said interrogator communication protocols as a recessive protocol, wherein said first interrogator communication protocol is a read only protocol consisting of a read mode and wherein said second interrogator communication protocol is a read/write protocol consisting of a read mode and a write mode, said system comprising:

• an interrogator programmed to transmit an interrogation signal according to the first or second interrogation communication protocol, and
• a transponder having circuitry to detect said transmission interrogation signal;
• the transponder further having circuitry arranged so that if the transponder detects said recessive protocol, said transponder switches automatically to said recessive protocol according to a reluctance rule based on the dominant protocol of the transponder and a first set of signal characteristics associated with said interrogation signal detected by the transponder;
• and wherein if the transponder detects said dominant protocol, said transponder reverts automatically to the dominant protocol according to an acceptance rule based on the dominant protocol of the transponder and on a second set of signal characteristics associated with the interrogation signal detected by the transponder;
• wherein a first set of reluctance and acceptance rules for the first interrogator communication protocol and a second set of reluctance and acceptance rules for the second interrogator communication protocol are programmed into the transponder's hardware, the transponder responding according to said first set of reluctance and acceptance rules based on a programmed bit designating the first interrogator communication protocol as the dominant protocol or the transponder responding according to said second set of reluctance and acceptance rules based on said programmed bit designating the second interrogator communication protocol as the dominant protocol.