My very old MIT Digital Interface has 4 switches.

And, just what do they do?
Here's a question that may stump the panel. I have a 17 year old (according to MIT) digital, RCA-terminated i/c that I recently acquired. It's labeled, "MIT Digital Interface", in blue on one side of its gray "magic box". On the other, are four white side-by-side rocker switches in a red rectangle. Across the top, they are labeled 1, 2, 3, and 4. Underneath them, is the word, "OPEN".
Just what the heck do they do? What do they "open" (besides a customer's wallet)? The cable is so old, even the folks at MIT don't know anymore.
I'd appreciate any help you can give me. Thanks.
Audio Advisor used to clear them out (8-9 yrs ago). The switches are used to match the impedence of transports and your dac. I have not owned one but had considered one a long time ago.

Hope it helps.
Thanks, Gene:
I suspected as much, since impedance matching is, generally, what MIT's network boxes are all about.
I'll just use my ears to determine the best setting.