The TR-5 unit has one function only, individual input voltages and a single time range; the TR-6816U has eight functions (you will need to select one of these 8 to match the function on the obsolete TR-5 product), universal voltage of 24-240V AC & 12-125V DC and 16 timing ranges covering 0.05 seconds — 100 hours (you will need to select one of these ranges and then adjust within that range to match the obsolete TR-5 product). Contact Macromatic for additional information & technical support.