Difference between 75 and 110 ohm digital cables?


If buying an rca digital cable from transport to dac what are the differences between these 2 types of cables? 
rsf507
75 or 110ohm is characteristic impedance of the cable.  It should match output impedance of the transport and input impedance of the DAC.  In audio most of the time single ended connection with RCA or BNC connector is specified at 75ohm while differential one with XLR connectors is specified at 110ohm.
110 is the spec for balanced connections. 75 would be typical for single ended , i.e. RCA