Is an I2S cable a Cat 5, 6 or 7 Ethernet cable, or are they two different beasts?

Alan,

So I2S has nothing to do with a specific cable.  It's a defined transmission protocol that a DAC may be designed to use as one of its inputs, laying out what internally wired pins are used.

Given that, then some cables with J45 connectors that are labeled as I2S, like the Stealth, may or may not have only the internal wires that the I2S specifically needs.  This would make them not usable as a standard Ethernet cable.

Does this sound correct and why a cable manufacturer would specify that it's an I2S cable?

Thanks!

The Stealth I2S cable can be used as a standard eithernet cable of course at a ridiculous price
Alan

I2S is the protocol used within a DAC for moving data from point to point.  There are some devices that can transmit data in this form and DACs that will accept it in that form.  Doing so avoids two steps of data conversion and can lead to better sound.  PS Audio and Wyred 4 Sound are a couple of manufacturers that come to mind that use this.  For both of those manufacturers they use a standard HDMI cable to transmit the data.  CAT 5/6/7 are all Ethernet data cables for transmission of data between computers, completely different from I2S.

But of course you can use  CAT 5/6/7 cables for I2S connection 
Alan