Abstract: A multi-function terminal having a built-in microprocessor for use as a point of sale station in a retail goods or services facility. The terminal has a membrane keyboard with arrays of keys for data entry, arranged in key blocks. The individual key blocks preferably relate to particular attributes of the goods or services as well as processing costs. A particular designation of the keys can be changed by substituting a replaceable overlay. The overlays are sized to cover individual key blocks. The terminal also has a magnetic strip and bar code reader and decoder. The terminal can drive two printers through parallel ports. The terminal also has circuitry for driving an LED display and facilities for accepting various types of monitor drivers for driving a video monitor. The terminal interfaces with a host computer which controls operating parameters such as the mapping of characters to particular keys and the decoding convention used by the bar code and magnetic stripe decoders.