Industry digital system
A metal keypad is a set of buttons arranged in a block or "pad" which bear digits, symbols or alphabetical letters. Pads mostly containing numbers are called a numeric keypad. Numeric keypads are found on alphanumeric keyboards and on other devices which require mainly numeric input such as calculators, push-button telephones, self-service terminal ,Ticket vending machines, renting,gas stations, Internet public telephone ,
Industrial automation,access control,food industry,chemical industry,info points,multimedia kiosk,military equipments,payment system,video telephone, ATMs, Point of Sale devices, combination locks, and digital door locks. Many devices follow the E.161 standard for their arrangement.