The insertion of impedance into a circuit to change the characteristics of the circuit. 2. In multichannel communications systems, the insertion of white noise or equivalent dummy traffic at a specified level to simulate system traffic and thus enable analysis of system performance. 3. In telephone systems, the load, i.e., power level, imposed by the busy hour traffic. Note 1: The loading may be expressed as (a) the equivalent mean power and the peak power as a function of the number of voice channels or (b) the equivalent power of a multichannel complex or signal composite referred to zero transmission level point (0TLP. ) Note 2: Loading is a function of the number of channels and the specified voice channel mean power.