Velleman K6400 Code Lockmore than 3000 codes (4 digits) relay output: 5A 110V time limit for code entry: + 5 seconds power supply: 9 15V DC or 8 12V AC VELLEMAN K6400 CODE LOCK KIT. This code lock may be used to switch an alarm (e. g. car alarm K3504) on and off, or to open a door lock. An LED on the operating panel indicates the position of the 'lock'. The code is easy to define. Because the operation panel is completely enclosed, it may be used inside and outside the house.