About PLANET Barcodes
PLANET (Postal Alpha Numeric Encoding Technique) is a legacy postal barcode symbology that was used by the United States Postal Service (USPS) for tracking bulk mailings. It worked in tandem with the POSTNET barcode. While POSTNET encoded the delivery destination zip code, PLANET encoded tracking numbers to let mailers know when their mail was processed. It has since been retired in favor of the Intelligent Mail Barcode (IMb).
How PLANET Encoding Works
PLANET is structurally very similar to POSTNET, using groups of five tall and short vertical bars to represent digits. However, the coding scheme is inverted: while POSTNET uses two tall bars out of five, PLANET uses three tall bars out of five. It encodes 11 or 13 digits, representing the service class, mailer ID, and sequential tracking number, ending with a modulo-10 checksum.
Common Applications and Industries
PLANET barcodes were printed on subscription renewal envelopes, credit card statements, and utility bills. When a customer mailed their payment envelope back, USPS sorting machines scanned the PLANET barcode, allowing businesses to monitor payment flows and schedule collections. This provided basic tracking before the internet era.
Advantages & Limitations
PLANET gave companies visibility into their return mail streams, helping them manage billing cycles. It used the same printer hardware as POSTNET. The limitation is that it required two separate barcodes on an envelope (one for routing and one for tracking), which took up excessive envelope space and was replaced by the single IMb code.