Yeah, they both have micro usb. The Note3 is usb 3.0, but backward compatible to 2.0. I'm just using a normal micro usb.

I had to figure out that the OTG cable is not "just" an adapter. Not sure if there's a chip or something inside, but the cable itself communicates with the device, telling the device that it is now the host/master. (Normally a phone is the slave when connected to a device via USB.)

My big breakthrough was figuring out that the OTG feature is built into the hotwire device, meaning that I don't actually need the special OTG cable. Atleast I don't need the special cable when using my Note3.

(I already purchased the real OTG cable, so when it arrives I can report back if I find that the Razr works any better with that cable. I discovered that the Razr doesn't power a device through it's USB, wherease the Note3 will power a device. So maybe with the correct cable and a battery in the car, the Razr will work? It'd be nice, but not a big deal.)