Which gate only sends one through if neither of its terminals receives a pulse.

NOR gate is a digital logic gate. It implements logical NOR. It behaves according to the truth table to the right. A HIGH output (1) results if both the inputs to the gate are LOW (0). If one or both input is HIGH (1), a LOW output (0) results. NOR is the result of the negation of the OR operator. It can also be seen as an AND gate with all the inputs inverted. NOR is a functionally complete operation. It combinations of NOR gates can be combined to generate any other logical function.