what is the range of a key fob
Remote keyless system Keyless remotes contain a short-range radio transmitter, and must be within a certain range, usually 5–20 meters, of the car to work. When a button is pushed, it sends a coded signal by radio waves to a receiver unit in the car, which locks or unlocks the door. Most RKEs operate at a frequency of 315 MHz for North America-made cars and at 433.92 MHz for European, Japanese and Asian cars. Modern systems since the mid-1990s implement encryption as well as rotating entry codes to prevent car thieves from intercepting and spoofing the signal.[3] Earlier systems used infrared instead of radio signals to unlock the vehicle, such as systems found on Mercedes-Benz,[4] BMW[5] and other manufacturers.
Function key Under MS-DOS, individual programs could decide what each function key meant to them, and the command line had its own actions (e.g., F3 copied to the current command prompt words from the previous command). Following the IBM Common User Access guidelines, the F1 key gradually became universally associated with Help in most early Windows programs. To this day, Microsoft Office programs running in Windows list F1 as the key for Help in the Help menu. Internet Explorer in Windows does not list this keystroke in the help menu, but still responds with a help window. F3 is commonly used to activate a search function in applications, often cycling through results on successive presses of the key. ⇧ Shift+F3 is often used to search backwards. Some applications such as Visual Studio support Control+F3 as a means of searching for the currently highlighted text elsewhere in a document. F5 is also commonly used as a reload key in many web browsers and other applications, while F11 activates the full screen/kiosk mode on most browsers. Under the Windows environment, Alt+F4 is commonly used to quit an application; Ctrl+F4 will often close a portion of the application, such as a document or tab. F10 generally activates the menu bar, while ⇧ Shift+F10 activates a context menu. F2 is used in many Windows applications such as Windows Explorer, Excel, Visual Studio and other programs to access file or cell edit functions.