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.