Reference Digital Audio 40 utilizes a carefully engineered geometry to achieve the precise characteristic impedance required for the maximum transfer of S/PDIF signals. Silver plated conductors deliver a low resistance path for high frequencies and QED "Digiloc" plugs more closely match the cable's characteristic impedance, reducing return loss by up to 1dB when compared to conventional RCA plugs. This ensures optimal signal transfer and improved micro-timing of the audio signal.