"However what is the FUNCTION OF THE DEVICE they attach to the end of the cable, usually by identified by a number like DBS v72?? It also has a small push button and green LED"
The button and LED are just to check the charge of the batteries. As to how it works, here's a link to AQ's description of DBS from their web site.
I could try to explain it, but the link does a much better job. But I guess the real question is "Does it work?". My answer to that would have to be, it most likely does. lol. The only way for me to be certain if the DBS really works is to get the same exact cable without DBS, or get 2 pairs of exactly the same DBS cable and disconnect the DBS system from one of the cables and let it sit for a long enough time until the effects of the DBS dissipates from the cable. It could be done either way, but I haven't. The reason I say it probably works is that the DBS cables, overall, sound very good and I notice very short break in periods, as well as some of the other claims AQ makes. Not only that, AQ has been using the DBS for a very long time now, and they sell tons of cables. Its no guarantee, of course, but I own many pairs of the cables and am very happy with them. I leave it at that.
Where you can get some very good deals on used AQ cables is if you look at the different generations. For example, look at the Jaguar IC. It started out as a 12V DBS cable. Then it went from 12v to 24v to 36v. Its essentially the same cable; just a different DBS voltage. From there they upped the voltage to 48v and changed the rca/xlr connectors and called it the Columbia. But if you look at it, its still pretty much the same cable as the original Jaguar. I use this example because I do own several pairs of Jaguar and Columbia in different voltages. I've put them side by side and can hear some fairly small differences between them. But I wouldn't bet money if someone wanted to test me. What I find most impressive is that I put them next to cables that cost a lot more, and they hold their own. Same thing with the CV-8. I have 2 runs of them on my Vandersteen's. I could use my TARA The 2's at $3800 but I still prefer the AQ.
Anyway, I hope this info can help you out. You made an excellent choice with your speakers. You'll have no problem finding a good pair of cables to match them.