Default OTG or regular USB cable for external keyboard?

I have been using a ps2-active usb adapter to run my old clicky keyboard to my A200, but thought that I will be upgrading to a 500 or 510 or 700 shortly so was going to try a micro usb-> female full sized usb cable since the full sized usb port is missing on most current tablets. I bought one on amazon but didn't get any connection and then saw it was a OTG cable after I ordered. I wasn't even sure to check first hand if there is any difference between a micro -> female full usb port cable that is OTG vs. non-OTG... or if I just have a defective cable.