Method and apparatus for tracking items using dual frequency tags

An apparatus comprising:

• a tag having circuitry which includes a receiver section and a transmitter section, said receiver section being operable to receive wireless signpost signals that each include a signpost code, and said transmitter section being operable to transmit wireless beacon signals which each include a beacon code associated with said tag, said transmitter section being responsive to receipt by said receiver section of a respective said signpost signal for including in at least one said beacon signal the signpost code from the received signpost signal;
• a signpost which is physically separate from said tag and which transmits said signpost signals to said tag;
• and
• a reader which is physically separate from said signpost and said tag, and which receives said beacon signals;
• wherein said signpost is configured to transmit said wireless signpost signals as near field signals of primarily magnetic character, and said receiver section is configured to receive said signpost signals of magnetic character.

A method comprising the steps of:

• transmitting signpost signals from a signpost, said signpost signals each including a signpost code and being a near field signal of primarily magnetic character;
• receiving said signpost signals in a receiver section of circuitry of a tag which is physically separate from said signpost;
• transmitting from a transmitter section of said circuitry of said tag wireless beacon signals which each include a beacon code associated with said tag, said transmitting step including the step of causing said transmitter section to be responsive to receipt by said receiver section of a respective said signpost signal for including in at least one said beacon signal the signpost code from the received signpost signal;
• receiving said beacons signals in a reader which is physically separate from said signpost and said tag.