Impedance is the resistance of audio circuits to audio signals. Any audio input has an impedance, as does any audio output. Modern input stages are typically high impedance, often 10 kOhms or higher. These inputs accept the input signal without demanding power from the prior equipment output. For accurate amplification, it is generally accepted that an audio input impedance should be higher than the output impedance of the prior device. The output impedance of RDL modules is typically 150 Ohms. The input impedance of RDL products is typically 10 kOhms. This makes all RDL outputs compatible with all RDL inputs. For the user, it is only important to remember that the input impedance should always be higher than the source impedance of the device driving the input. It cannot be the other way around. A high impedance output should never be used to drive a low impedance input. Such connections result in signal loss, quality degradation, and sometimes damage to the output of the source.