United States 5-Digit ZIP Code Database - Standard Edition Schema Copyright (C) 2005 www.datanetworksource.com All rights reserved. United States 5-digit ZIP Code Standard Edition data master. Default (preferred) city name recognized by the USPS Default (preferred) organization name recognized by the USPS Alternate city name accepted by the USPS Not-recommended, used or accepted, by the USPS Standard delivery PO Box Only Organization Military