SPDIF cable same as coaxial cable?

 I believe  all digital connections are limited to 24/192 except USB, any I2S implementation or ethernet. Someone else will need to chime in on what's best, redbook CD, 24/96 or 24/192 is very hard for me to tell much difference. 

I used a spare RCA interconnect (nominally 50Ω) for Spdif when I first got a DAC, it worked but a cable designed for the job but with RCAs on both ends was quite an improvement and a 75Ω cable with BNC connectors (Belden 4794R) better still even though it was designed for 12G SDI video and I had to use an adaptor at the DAC end because Rega didn’t see fit to put a BNC socket to their DAC. I think they were all coax cables.

It’s worth mentioning that a “composite video” cable is also the same as a digital coaxial cable...same 75 ohm characteristic impedance, same bandwidth. A good AQ YIQ or Monster Silver Digital from yesteryear serves nicely...

Also, one reason often given for preferring coax over optical is that the addition of an LED and photoelectric receiver to the signal path cannot, in most cases, help, when the signal originated as and must return to electronic impulses. 

I believe it’s moot. Digital data is just that. Until it’s processed by a dac, it’s just ones and zeros. Without form, without sound, going where no man has gone before.