USPS uses Intelligent Mail Barcodes (IMb) to label the items it carries with a unique identity in the form of a fluorescent pattern on the back and a black version on the front. This is completed automatically by machines that can read hand written or printed addresses. The collection and delivery service follows a standard spoke and hub format to connect sorting depots in ever increasing sizes. The hubs are divided into; Network Distribution Centres, Auxiliary Sort facilities, Sectional Centre Facilities and Destination Delivery Units. Distances of under 200 miles are generally covered by trucks and vans, while anything further away is transported by air. The USPS system is used by companies like UPS and FedEx where it fits in with their schedules, particularly to rural areas, which brings in additional revenue. Similarly, UPS has an agreement to deliver first Class and Priority Post for USPS across 98 US cities. The company now employs over 700,000 workers to handle the annual load of 213 billion items.emove pages use the Pages tab.
There are a number of different mailing options with USPS with price dependant upon the service, size and weight of the item. Express Mail is used for letters, envelopes, tubes and packaged items with a two day delivery schedule including basic insurance. Priority Mail is slightly slower but cheaper; both options have a maximum weight limit of 70 pounds and length of 108 inches. First Class Mail does not set a specific delivery time period although it does not normally exceed three days. Parcel Post is described as the affordable and reliable way to send packages, but again with the same weight and size limitations of Express Mail. Media Mail is usually the cheapest option but is limited to books, manuscripts and other readable media formats.
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