Impulse response of energy-efficient multiband RF-interconnect (MRFI) is analyzed to quantify its information capacity for transmitting digital data via various types of physical wires. Our analyses in frequency domain (also transferrable to time domain if needed) indicate that a baseband-equivalent impulse response can be established for MRFI under coherently communicated systems. We can further express such response in an explicit form for MRFI with low-pass transmission nature. It also reveals its distinct capability in signal equalization as a result of its RF-carrier down-conversion process. Furthermore, the analysis offers a guidance of how to construct baseband-equivalent impulse response when transmission lines contain non-ideal effects such as frequency notches and in-band ripples.