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Address Information System products

Address Information System products, or AIS products, are raw USPS database files that help customers standardize addresses, get address details and correct address records. Mailers read them with matching software they buy or build, and get a new release each month.

Updated October 31, 202642 sources

What it is

AIS products include applications and electronic files, from the ZIP + 4 Product to ZIPMove. Each file holds raw data and no software. Each product is a master file with every record in the areas the customer ordered. The records are sorted in ascending order by ZIP Code and Update Key Number.

Mailers use AIS products to cut undeliverable-as-addressed mail, automate more of their mail and qualify more pieces for postage discounts. Most companies that add ZIP + 4 codes to their lists buy CASS Certified address-matching software or hire a service bureau that runs it. USPS suggests building matching software only for very large files, special needs or a system to sell, since it is an expensive investment.

How it works

AIS products come through Electronic Product Fulfillment, a USPS website that posts each release for download. All AIS products are sold as annual subscriptions and issued monthly.

  1. Submit the Electronic Product Fulfillment Web Access Request Form to open an account.
  2. Order the products on the AIS Products Order Form.
  3. Watch for the email that says a release is posted and ready to download.
  4. Build an address-matching directory from the release for the matching software to read.
  5. Renew the subscription every 12 months.

A product bought one time only costs 90% of the base price. USPS sends a renewal notice through Electronic Product Fulfillment 60 days before a subscription expires.

ZIP + 4 Product

The ZIP + 4 Product is the base file that matching software reads to assign the right ZIP + 4 code to a mailing address. It holds detailed street data, but only the City State Product lists every 5-digit ZIP Code and city name. It comes through Electronic Product Fulfillment every month.

Each release includes a transaction file of the records added to or deleted from the base file. Its Action Code marks each record as an add or a delete. A change shows as a delete and an add together.

A Record Type Code in each record says what kind of delivery it covers.

CodeRecord typeWhat one record covers
SStreetA range of addresses on a street block, one side of a street, a cove or a cul-de-sac.
PPO BoxOne Post Office Box, or a range of boxes that share a ZIP Add-on code.
RRural route or contractRural routes with box deliveries.
HHigh-riseA building, apartment complex, floor or other place other than a street.
FFirmA business or organization that gets a locally set minimum of machinable letters each day.
GGeneral deliveryThe ZIP + 4 code for general delivery mail in a ZIP Code.

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City State Product

The City State Product is a list of ZIP Codes with their city and county names. It also holds the other names a Post Office goes by. Matching software uses it to check the city name and ZIP Code in an address, and to link the other AIS products' records. It holds about 100,000 records.

That list is the City State portion of the product, which has other portions as well.

  • Street Alias records hold every street alias and primary street name, so software can find a street's new name.
  • Zone Split records list ZIP Codes whose carrier routes were reorganized in the past eighteen months.
  • P.O. Box Only records mark communities where a P.O. Box is the only form of delivery a customer can get.
  • Seasonal records give the months each ZIP Code's seasonal addresses count as occupied.

The City State Product has no detailed street data. Complete 5-digit ZIP coding needs it together with the Five-Digit ZIP, ZIP + 4 or Carrier Route Product. It comes at no extra charge with an order for the Carrier Route, ZIP + 4, Five-Digit ZIP or eLOT product.

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Linking the files

City State Keys in the other files link each record to the City State Product, which holds its preferred city name.

To find the preferred city name for a ZIP + 4 record:

  1. Take the Preferred Last Line City State Key from the ZIP + 4 record.
  2. Match it to the City State Key in the City State Product.
  3. Read the preferred last-line name in that record's City State Name field.

The same steps with the Urbanization City State Key give an urbanization name, which exists only for records in Puerto Rico.

Cross State supplemental files

The Cross State Supplemental file lets the City State and ZIP + 4 products recognize ZIP Codes that include deliveries in a neighboring state. City State Product customers append the supplemental City State file to the City State Product. ZIP + 4 Product customers use the Update Key Number to replace a ZIP + 4 record with its supplemental record. The replaced record then returns the state where the address lies from the supplemental City State file.

Five-Digit ZIP Product

The Five-Digit ZIP Product gives matching software 5-digit ZIP Codes to add to computerized mailing lists. It holds ranged street data only for cities with more than one delivery ZIP Code. A complete list of ZIP Codes for every city is only in the City State Product. Complete 5-digit ZIP coding needs both products. Updates come monthly through Electronic Product Fulfillment.

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Carrier Route Product

The Carrier Route Product gives mailers the data to put carrier route codes on addresses for presort postage discounts. Mail with carrier route codes can then be presorted to the carrier route level.

Its records include type M, a single address served by more than one carrier. Post Office Boxes are grouped by box section, which counts as a carrier route for presorted mail. The AIS Viewer's ZIP + 4 Retrieval option replaced the product's old hardcopy report.

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Enhanced Line of Travel

Enhanced Line of Travel, eLOT, is the AIS product that lets mailers sort mail in about the order a carrier cases it. Each eLOT record gives a range of ZIP + 4 codes on a carrier route a sequence number and an ascending or descending code. The sequence number marks the first delivery to that range on the route, and the code gives the delivery order within it. Mailers may use eLOT processing to qualify for enhanced carrier route presort discounts. Records without a ZIP + 4 code can't be used with eLOT.

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Delivery Statistics Product

The Delivery Statistics Product counts Post Office Boxes and business and residential deliveries on city, rural and highway contract routes for every ZIP Code. It keeps the counts by carrier route and Post Office Box section. Each record carries two City State Keys, the Municipality and the Preferred Last Line keys. The Municipality City State Key is left blank until further notice.

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Z4CHANGE Product

The Z4CHANGE Product shows which ZIP + 4 codes were realigned in the past twelve months. A mailer reprocesses only the records that had changes, monthly or bimonthly, instead of the whole list.

USPS regulations require every customer address list to be processed by CASS Certified software. Reprocessing whole lists often helps delivery but costs money and time. Z4CHANGE keeps a list qualified for automation prices without reprocessing it whole.

When USPS adds a high-rise or firm record, Z4CHANGE also flags its street ZIP + 4 code, so a mailer can upgrade street-level matches. Customers write their own software to read Z4CHANGE and pick the records to reprocess. After a significant change in CASS requirements, USPS may tell Z4CHANGE customers to reprocess their entire lists.

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ZIPMove Product

The ZIPMove Product helps matching software find accurate ZIP + 4 codes after a ZIP Code realignment changed an address's city name or finance number. Such a change usually keeps the software from finding the new ZIP Code. A finance number is the six-digit number USPS assigns to an installation for its financial data.

Each ZIPMove detail record has an Old Update Key Number field and a New Update Key Number field. USPS encourages mailers to run ZIPMove as a regular part of their address hygiene. Updates come monthly through Electronic Product Fulfillment.

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Residential Delivery Indicator

The Residential Delivery Indicator, RDI, is a data product that tells whether a delivery address is residential or business. Parcel shippers use it because some shipping companies charge more for residential delivery.

RDI comes as hash tables, not a flat file. The 9-digit table holds ZIP + 4 codes with only business deliveries. The 11-digit table holds the delivery point codes of business deliveries in ZIP + 4 codes that mix business and residential deliveries. A processed address returns Yes for a business or No for a residence.

Developers of third-party RDI software must be CASS software manufacturers or on their way to becoming one. A licensee may use RDI internally, offer it as a service to others or redistribute the data.

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AIS Viewer

The AIS Viewer is an interactive application that retrieves, views and prints ZIP Code information for all 50 states. It prints reports on demand at a 5-digit ZIP Code level.

The AIS Viewer has five options.

  • Address Lookup checks one address and returns its 5-digit ZIP Code, ZIP + 4 code, carrier route, county, delivery point and check digit codes.
  • City/State/Delivery Type lists ZIP Codes with their city, county and Post Office names.
  • County Name Retrieval gives the county or parish of a 5-digit ZIP Code.
  • Delivery Statistics Retrieval gives delivery counts by carrier route and Post Office Box section.
  • ZIP + 4 Retrieval prints reports of street records by city, state, ZIP Code or carrier route.

Address Lookup is free with at least one of the four other options, which are priced separately. The annual subscription includes 12 monthly updates. The data is encrypted and cannot be exported. Data stays valid for 105 days from each monthly cycle date.

Using the AIS Viewer with Address Lookup meets the 5-digit ZIP Code accuracy standard for addresses on non-automation presorted First-Class Mail, Periodicals, Standard Mail and Bound Printed Matter.

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Rules

The ZIP + 4® and City/State data must be updated by ZIP + 4 and City/State product users within 45 days of the USPS® release date (ref. USPS Domestic Mail Manual).

Users of the ZIP + 4 and City State products must load each release within 45 days of its USPS release date.

Both the City State product and ZIP + 4 product are required to perform complete ZIP + 4 encoding and validation.

A mailer must use both products to fully assign and check ZIP + 4 codes.

USPS requires address lists to be processed through CASS Certified ZIP + 4 address-matching software before being processed against the eLOT product.

An address list must go through CASS Certified ZIP + 4 software before it runs against eLOT.

LOT information must be updated within 90 days before the mailing date.

A mailer must update its line-of-travel information within the 90 days before each mailing date.

The RDI product must be used in conjunction with CASS Certified ZIP + 4 address matching software and may be used on any platform.

RDI must run alongside CASS Certified ZIP + 4 address-matching software. It may run on any platform.

Otherwise, Z4CHANGE customers will only be required to reprocess their entire address lists at the end of the third year following Z4CHANGE certification.

Z4CHANGE customers must reprocess their whole address lists at the end of the third year after their Z4CHANGE certification.

To identify the Cross State addresses, you must incorporate the Supplemental City State file in conjunction with the Supplemental ZIP+4 file.

A mailer must use the supplemental City State and ZIP + 4 files together to find cross-state addresses.

What goes wrong

When a ZIP Code isn't in the ZIP + 4 Product, the Zone Split records show whether a new ZIP Code was assigned. When a street finds no match, the Street Alias records give its other names to match on. A realignment that changed a city name or finance number keeps matching software from finding the new ZIP Code, which ZIPMove fixes.

Street segments with no possible delivery, such as those beside parks or railroad tracks, have no complete ZIP + 4 code. Their ZIP segment holds ND. A significant leading zero in an address number appears in the ZIP + 4 file as a hyphen. Firm names never appear on Post Office Box records, because USPS policy doesn't allow disclosing them.

Don't use Cross State as a city name, because the supplemental file uses it to mark cross-state records.

The AIS Viewer won't run on a Macintosh. It needs its DPV and LACSLink components enabled. USPS makes no refunds once an order is processed and its files are downloaded.

Terms

Address Information System productAIS product
A raw database file made available to customers to enhance address standardization, obtain detail address information, and correct address records. AIS products include applications and electronic files such as Carrier Route, City State, Delivery Statistics, Enhanced Line of Travel (eLOT), Five-Digit ZIP, TIGER/ZIP+4, Z4Change, ZIP+4, and ZIPMove. Also called address management product.
ZIP+4ZIP+4 CODE
An enhancement to the 5-digit ZIP Code that uses an additional four digits to represent the sector (a geographic area or neighborhood) and segment (a smaller unit such as a building, floor, street block) for an address within a 5-digit zone.
Carrier RouteCR, Carrier Route Identifier, Carrier Route Id
(1) The addresses to which a carrier delivers mail. In common usage, carrier route includes city routes, rural routes, highway contract routes, Post Office Box sections, and general delivery units. (2) A presort level in which all pieces in the bundle or container are addressed for delivery to the same city route, rural route, highway contract route, Post Office Box section, or general delivery unit. (3) A price category available for some mail classes or products prepared at a carrier route presort level.
finance number
An assigned six-digit number that identifies an installation or project for processing its financial data. The first two digits are a state or project code; the next four are uniquely assigned from 0001 through 9999 to each installation in alphabetic order. The finance number is used to measure and allocate cost and revenue to various cost centers.
zone split
A zone realignment in which some territory is taken from an existing ZIP Code and moved into another existing ZIP Code or into a new ZIP Code.
zone realignment
The process of moving territory from one or more ZIP Codes to an existing ZIP Code or a new ZIP Code. ZIP Code realignment generally occurs because of population growth and the expansion of delivery addresses and no new ZIP+4 codes can be assigned or reassigned.
line-of-travel sequenceLOT sequence
A presort level for certain price categories in which mailpieces are arranged by ZIP+4 codes in the order in which the route is served by the carrier. It is not an exact walk sequence but a sequence of ZIP+4 codes arranged in the order that the route is served by a carrier. (First the ZIP+4 groups are sequenced, then the addresses within each are identified as being in ascending or descending order.) The Enhanced Line of Travel (eLOT) addressing product provides a list of the ZIP+4 codes each carrier route serves, identifies the delivery order, and provides an indicator specifying whether the addresses that share the same ZIP+4 code must be sorted in ascending or descending order. When a range of ZIP+4 codes on the same carrier route are assigned the same sequence number, the addresses bearing those ZIP+4 codes must be arranged in ascending ZIP+4 code order before the sequence number is assigned. LOT information must be updated within 90 days before the mailing date. Unless the mail is prepared in carrier walk sequence, LOT sequence is required for mailings at Standard Mail and Periodicals carrier route basic prices.
Electronic Product FulfillmentEPF, Electronic Product Fulfillment (EPF) web site, Electronic Fulfillment Website
A secure web-based application managed by the National Customer Support Center in Memphis TN that is used to post and receive Address Management and Address Information System products, including ACS fulfillment files.
National Customer Support CenterNCSC, National Customer Service Center
An organization that provides information, services, and products (e.g., address management software programs such as the City State product, zone charts, directories, testing of ZIP+4 code or delivery point code address matching software) that improve addressing quality for mailings that qualify for certain prices.

Contacts

  • The Addressing and Geospatial Technology office answers questions about AIS products at 800-238-3150 or incsc@usps.gov.
  • The AIS Viewer's Customer Support Department is at 1-800-238-3150.
  • RDI questions go to (800) 238-3150 or AISProducts.NCSC@usps.gov.
  • First-time RDI buyers write to Customer Care at AISProducts.NCSC@usps.gov before ordering.
  • The CASS/MASS Department, at 800-642-2914, helps those who want to become CASS software manufacturers.

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