Yes, it's what kind of signal you're sending ... Simply put, since the USA uses 60 Hz electricity our TVs, cams, and other displays use the NTSC system which is designed to display 60 frames per second. In Europe the electricity is 50 Hz and then so are the TVs cams, and display systems (PAL) ... You can use either system provided your camera and display are both switched to the same setting (assuming both have that selectable feature). The transmitter doesn't care, it's just encoding whichever signal you're using and sending it along on a 5.8 GHz carrier to the receiver (which also doesn't care) that decodes it then sends that signal to the display.