Creating the checksum character If Customers don’t use proprietary software from PIF (Postcode Information File) or a Royal Mail approved co-supplier then they’ll need to work out the checksum character. This involves using an algorithm, as described below. The checksum character is used as a means of error detection to ensure that the rest of the barcode is correct. Creating the Delivery point Suffix (DPS) A Delivery Point Suffix consists of a number then a letter. • The number used can be 1-9, it cannot be a 0. • The letter can be any letter of the alphabet except for C,I,K,M,O or V. • Some addresses do not have a specific DPS. In such cases you should use a default DPS: 9U, 9W, 9X, 9Y or 9Z. Whichever default DPS you use is up to you and the same on can be used for all such addresses. There are a number of ways Customers can find out the correct Delivery Point Suffix, • Purchase the Postcode address File (PAF®) from Royal Mail. - The DPS will be included with PAF® if Customers take this in either Compressed Standard or Main file format. However, if Customers take the information in any other format, they’ll need to access the DPS through the Postcode Information Files(PIF®). • Purchase a PAF® Address Management package from a Value Added Reseller. - Customers will need to talk to their supplier to arrange access to the Postcode Information File data. • If you get address information from a bureau - The bureau can hard code their customer lists on an agency basis – much the same way as the Customer may already have your lists Post coded.They can add the DPS to the lists at the same time. Delivery Point Suffix Requirements For Access 70 CBC, a minimum of 90% of the mailing items must contain a CBC with an accurate DPS. The remaining mailing items (up to 10%) may contain a CBC with a default DPS. Hard coding lists Once a Postcode and DPS are allocated to an address, it is unlikely the address will change, although the address will change, although this may be necessary from time to time. It can therefore be beneficial to ‘hard code’ address lists with at least the DPS. This makes it easier to access the information needed for the barcode, for the addition of just two bytes per record (one kbyte per 500 records).
The checksum digit could also be hard coded, or could be allocated automatically at the time of printing through the use of a program.
Postcode Information File (PIF®) We offer a file which enables you to identify the exact delivery address when, for example, the Postcode is shared by several addresses, and match it to the correct DPS and checksum character. The file gives the Postcode, DPS and checksum character, plus an extra field (Delivery Point Data (DPD) that uniquely identifies the address for example:
At its most simple, the DPD will be the house number. For properties without a number, it will be a house name. For Large Letters, the relevant information from the Postcode Address File will appear.
Customers should link this file either to PIF® or to address list which have a high level of postcoding.
PIF® file size The sizes for the various elements in PIF® are:
Delivery Point Information
50 bytes 7 bytes 2 bytes
Postcode
Delivery Point Suffix Checksum character Total size per record
1 byte
60 bytes
With 27.5 million records, the total size of the file is 1,495 Mbytes. Format PIF® can be supplied on standard tape at 6250 bpi, ASCII or EBCDIC, with or without standard labels or IBM 3480 or IBM 3490E cartridges. Working out the checksum character Checksum characters can be automatically produced through the software available from co-suppliers.They are also available on the Postcode Information File (PIF®). They can however also be calculated by following the steps.
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