Does anyone have plans for a DIY secondary o2 sim?? I know there are different plans on the internet and such, but they all seem different.......can someone please post plans for one that you have seen work? I just dont want to pay for something that I can make for a couple of bucks.

 

I'm pretty sure they all work but most of the DIY ones are very simple in comparison to the one Zip or whatever his name makes. For lack of knowing better, his is more "precise".