A temperature sensing device for determining a temperature of a remote device , the remote device having a first controller which is clocked by a first crystal oscillator having a frequency-temperature characteristics, the first controller adapted to respond immediately or else a preset number of clock cycles later to communications from the temperature sensing device , the temperature sensing device comprising: a second controller which is clocked by a second crystal oscillator , wherein the clock speed of the clock signal of the second controller is higher than the clock speed of the clock signal of the first controller , wherein the temperature sensing device and the remote device communicate electronically with each other over a communication interface , wherein the second controller is adapted to: initiate a chain of repeated sequential communications between the temperature sensing device and the remote device ; each communication comprising transmission of a challenge signal to the remote device and reception of a response signal per challenge signal; measure time intervals presenting between transmissions of the challenge signals and receptions of the response signals associated with the chain of repeated communications; from the time intervals determine a clocking frequency of the first controller of the remote device ; and from the clocking frequency, determine a temperature based on knowledge of the frequency-temperature characteristics of the first crystal oscillator . a second controller which is clocked by a second crystal oscillator , wherein the clock speed of the clock signal of the second controller is higher than the clock speed of the clock signal of the first controller , wherein the temperature sensing device and the remote device communicate electronically with each other over a communication interface , wherein the second controller is adapted to: initiate a chain of repeated sequential communications between the temperature sensing device and the remote device ; each communication comprising transmission of a challenge signal to the remote device and reception of a response signal per challenge signal; measure time intervals presenting between transmissions of the challenge signals and receptions of the response signals associated with the chain of repeated communications; from the time intervals determine a clocking frequency of the first controller of the remote device ; and from the clocking frequency, determine a temperature based on knowledge of the frequency-temperature characteristics of the first crystal oscillator . initiate a chain of repeated sequential communications between the temperature sensing device and the remote device ; each communication comprising transmission of a challenge signal to the remote device and reception of a response signal per challenge signal; measure time intervals presenting between transmissions of the challenge signals and receptions of the response signals associated with the chain of repeated communications; from the time intervals determine a clocking frequency of the first controller of the remote device ; and from the clocking frequency, determine a temperature based on knowledge of the frequency-temperature characteristics of the first crystal oscillator . <EOS>