Multiline Optical Character Reader refers to a class of mail sorting machines that captures an image of the front of letter-sized mail, uses Optical Character Recognition (OCR) technology to find and decode the entire address, looks up the ZIP+4 code and Delivery point, sprays a POSTNET barcode representing this information on the mailpiece, and preforms an initial sort. All this occurs in a fraction of a second as the mailpiece passes through the machine. After this point, mail is further sorted by barcode sorters that read this POSTNET barcode to determine it destination throughout its journey all the way down to the walk sequence of the mail carrier. Optical character recognition, usually abbreviated to OCR, involves computer software designed to translate images of typewritten text (usually captured by a scanner) into machine-editable text, or to translate pictures of characters into a standard encoding scheme representing them in (ASCII or Unicode). ... In a postal system, a delivery point (sometimes DP) is a single mailbox or other place at which mail is delivered. ... POSTNET is a barcode symbology that is used by the United States Postal Service to assist in directing mail. ...

If the MLOCR is not able to decode the address (usually due to being handwritten), a unique fluorescent barcode is sprayed on the back of the mailpiece, and these un-coded letters are set aside while the Remote Bar Coding System (formerly called Remote Video Encoding) scrutinizes these. An image of the mailpiece is sent to a Remote Encoding Center where more powerful computers or human operators determine the address and ZIP+4 code. This data is sent back to the MLOCR site where it is matched with the unique barcodes on the back of the un-coded mailpieces, and these pieces finally are given a POSTNET barcode like the rest of the mail. All this effort is put into deciphering these mailpieces so that they never need to be examined again.

The United States Postal Service is the largest users of these machines, however large volume mailers and mail consolidators also use MLOCRs to barcode outgoing mail in order to receive significant postage discounts. A USPS truck in San Francisco A smaller truck used in suburban areas This article describes the United States Postal Service. ...

An option called FASTforward [1] can be added to an MLOCR that allows it to automatically forward mail to a new address. This additional computer hardware/software combination looks up decoded addresses in the National Change of Address database to see if the recipient has recently moved. If so, a POSTNET barcode representing the new address is sprayed on the mailpiece thus routing it to new address although the old address is still visible—a testament to the fact that mail is sorted entirely by machines in the United States today. A USPS Truck at Night A U.S. Post Office sign The United States Postal Service (USPS) is the United States government organization responsible for providing postal service in the United States and is generally referred to as the post office. ...