ABSTRACT
Products that require numeric entry should use a telephone-style keypad layout, which presents the 1-2-3- keys in the top row, to prevent incorrect entries due to muscle memory-related errors. Numeric keypads on telephones and calculators usually have different key layouts. With little deviation based on the manufacturer, telephone keypads typically present the 1-2-3 keys in a row at the top, whereas calculator keypads typically present them in a row at the bottom. The emerging consensus among human factors engineering specialists is that the telephone-style keypad is slightly better for applications requiring number pads. The justification is that people frequently typing on telephones and using their mobile phones develop muscle memory of where to find the keys. The National Patient Safety Agency’s guidance document titled “A Guide to the Design of Electronic Infusion Devices” recommends using the telephone layout for all infusion devices.
