In order to obtain a read from a barcode you need a reading head (to measure the bars and spaces) and a decoder (to decode this data into characters). Reading of barcodes can be performed using barcode scanners (generally for stationary reading) or Portable Data Terminals (for use on location).

Bar code readers come in various shapes and sizes and can be hand operated or mounted alongside a fixed location or even a conveyor system (such as the flat bed types found in supermarkets).

The reader, or scanner, might be connected directly to a computer system, in which case an operator will be able to observe the scanned data on a computer monitor as it is scanned. Computer software will generally use the data, which would indicate a part or item identification number, to request additional information about the item from a database, or will update a database record with time and date details about this item.

Portable Data-capture Terminals (PDTs)
Sometimes, the bar code will need to be scanned at a location away from any computers and in these situations portable data collection equipment, with either a connected or built in scanner, will be used to record the data in the bar code along with other relevant information about the function that is being performed.

Various portable data collection devices will also have the capability to communicate using radio waves to centralised computer systems in a warehouse or manufacturing facility and in these situations some processing of the scanned data can take place almost immediately.