Readster,
My understanding is a digital cables impedance, inductance, total length, internal reflectance and quality of terminations all play a role in its ability to preserve data.
Lots of discussion here at Audiogon on the subject, including the concept of maintaining 75 ohms as that is supposed to be the standard.
Then there is the issue of whether the DAC and transport are TRUE 75 ohm and would benefit from that exact termination.
Connectors play a role, with BNC type claiming to be "the" 75 ohm standard. In response, Canare built an RCA version that is reported to be just as accurate.
So as usual, the answer is not easy and why many of us choose to audition various cable to determine what works.