The Postnet (postal numeric encoding technology) barcode was developed by the United States Postal Service to encode postal codes into characters for quick and reliable sorting with the help of BCS. This barcode can encode ZIP, ZIP+4, and ZIP+4+2 postal codes.

Postnet barcodes can encode 0-9 digits. A barcode consists of a short bar and a long bar. Each symbol of data is encoded using 5 bars. This barcode always contains exactly one check symbol calculated with the modulo 10 algorithm.

"Postnet" barcode. "11387975204" is the number encoded in the barcode.