Hi
The I2S is a digital interface designed to go between a cd transport and a digital to analog converter or DAC.It suppost to be a better connection because it transmits the signal's clock and data seperately,and so it reduces the jitter.Now jitter is timing errors and contributes to distortion and sound deterioration in a high resolution system.Audio Alchemy,Camelot Technologies,Sonic Frontiers and few other companies were using I2S but I believe Audio Alchemy was among the first perhaps they even pioneered the technology.
The DTI PRO 32 is an antijitter device,and a good one at it.Other similar devices were the Genesis digital lens,Sonic Frontiers Ultrajitterbug,Camelot Dragon,Monarchy DIP,Theta TLC to name a few.The best one was the digital lens much better engineered to the task and more expensive to boot,of these I own two units in my system and they do a fabulus job smoothing out my digital setup.i got two ultrajitterbugs as well.
I was going to buy a DTI PRO 32 but changed my mind a while ago to lack of support in case of failure,although the digital lens is in similar case.
The DDEv1.1 was my very first external DAC back in the day,this I am talking about 1992 and what a good little unit it was!!!! I ended up giving to my brother who used it a lot and I believe has it still in a closet in Greece.
I am not sure about the price on I2S digital cables but i would recommend to shop for used ones even though the I2S interface is not as popular anymore.
Best regards
George