This item in stockLinear MDTK Megacode garage door opener digital keypad transmitter 318 MHZ. The MDTK digital keypad is one of Linear's Megacode series of wireless radio controls designed for use with automatic garage door and gate operaters. The Megacode radio format provides unparalleled security with more than a million different codes.In operation, the user enters their unique code on the unit's keypad ( 1 to 6 digits long ) and presses the START/STOP button to activate the door operator. For up to 30 seconds after the last activation, the MDTK can be re-triggered by simply pressing the START/STOP button again. This allows the user to stop or reverse the garage door opener quickly, without having to re-enter their code.The MDTK has built-in keypad lighting for use at night or in dark areas. The clear silicone keys are backlit with a pleasing green glow. By pressing the START/STOP button first, before entering their code, the user can light up the keypad. Pressing the START/STOP button twice at any time will light up the keypad.The keypad lockout timer will disable the keypad after 10 activations. The keypad must remain idle for 30 seconds before new attempts.Megacode receivers are programmed by sending a signal from the user's transmitters. This stores the transmitter's code into the receiver's memory The receiver will retain its memory without power and will only activate from these memorized transmitters. Each MDTK keypad code can be considered a different transmitter. Each Megacode receiver can remember a maximum of 10 transmitters ( 40 for gate receivers ). Any combination of portable transmitters and keypad codes up to the maximum number can be entered.