The two main types of barcodes used in libraries are Code 39 and Codabar.
Code 39 was the first alphanumeric symbology to be developed. The rectangle of lines and spaces translates into 10 digits, but they are not displayed. The first digit is used to identify whether the barcode is for a patron or an item. The next two digits identify the institution. The last seven digits are a unique code which represent either a patron or an item.
Codabar barcodes are the most frequently used barcodes in libraries. The rectangle of lines and spaces translates into 14 digits. The first digit is used to identify whether the barcode is for a patron or an item. The next four digits identify the institution. The following eight digits represent patron or item information, and the final digit is an error-checking digit. See image:
Libraries that are part of the South Dakota Library Network use codabar barcodes. To provide consistency across the state it is recommended that South Dakota libraries use codabar barcodes. It is also recommended that before ordering barcodes, libraries contact the South Dakota Library Network. The staff at SDLN can assign your library a barcode number. Your library does not have to be an SDLN member to receive this service. Making use of this service guarantees that your library's barcode number will not duplicate another library's barcode number. It also ensures that should a library want to join SDLN in the future their barcodes will be compatible.
The SDLN staff can be contacted at 1-800-245-5690 or staff@sdln.net.