System and method for detecting transponders used with printer media

A method of detecting a transponder communication location on media, said method comprising:

• attempting to communicate with the transponder using a transceiver;
• detecting at least one successful attempt to communicate with the transponder;
• detecting at least one unsuccessful attempt to communicate with the transponder;
• and
• locating the transponder relative to the transceiver based on the at least one unsuccessful and one successful communication with the transponder.

For use in apparatus in which a passive RF transponder is located in the field of an RF transceiver configured to communicate with the transponder, a method for determining when a predetermined state of communication between the transponder and transceiver exists, the method comprising:

• causing the transceiver to send a signal to the transducer and sensing a characteristic of the signal that is returned by the transponder;
• one or more times adjusting a parameter of the communication link established to cause the signal returned by the transponder to change;
• and
• determining from the parameter adjustments and return signal variations when a predetermined state of communication exists between the transponder and the transceiver.

For use in a thermal printer in which a label carrying a passive RFID transponder is located in the field of an RF transceiver configured to communicate with the transponder for purposes of encoding or reading the transducer, a method for determining when an optimal or acceptable state of communication exists between the transponder and transceiver, the method comprising:

• causing the transceiver to send a signal to the transducer and sensing the amplitude or power of the signal that is returned by the transponder;
• one or more times adjusting the power of the transceiver or the physical location of the transponder to cause the signal returned by the transponder to change;
• and
• determining from the return signal variations that occur when transceiver power or transponder location adjustments are made when a state of optimal or acceptable communication exists between the transponder and the transceiver.