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PostBar, also known as CPC 4-State, is the black-ink barcode system used by Image:CPC PostBar legend.svg" TITLE="Canada Post in its automated mail sorting and delivery operations. It is similar to other 4 State barcode systems used by Australia Post and the United Kingdom's Royal Mail (from which it derives), but uses an obscured structure and encoding system unique to Canada Post. This particular bar code system is used on "flats" (which are larger-than-letter-size pieces of mail, such as magazines) and parcels. Image:CPC PostBar legend.svg">rightsymbology also uses an element known as a ''Data Content Identifier'' (or DCI), which specifies what types of information are encoded into each barcode, such as postal codes, customer information, and exact delivery points. The information that goes into each barcode is obtained from the address printed on the front of the envelope it is ultimately printed on, as well as the physical dimensions of each piece of mail. This code also uses a Reed-Solomon error correction technique, so that in case a particular piece of mail is mishandled, the information encoded in the barcode can still be correctly decoded. ==Character sets== Four character sets are used in PostBar codes, known as "A", "N", "Z" and "B" characters. Three-bar A characters are used exclusively to encode letters, and two-bar N characters encode only digits. Three-bar Z characters can encode either letters or digits. A and N characters are typically used to encode postal codes and country codes. Z characters are used for address locators, product types, and customer and service information. B characters are one bar each, and are used to encode base-4 machine IDs for Canada Post's internal uses. The bars making up a character can be interpreted as base-3 digits. A full height bar encodes 0, a short lower bar (an ascender) encodes 1, and a short upper bar (a descender) encodes 2. The leftmost bar in a group is the most significant trit, and may have the value 3, with both upper and lower bars short (a tracker). In other words, short upper and lower bars are assigned weights of 18 & 9, 6 & 3, and 2 & 1, from left to right. Since the first bar has 4 possible values, and the following bars have 3, 2 bars can encode 4×3 = 12 values, while 3 bars can encode 4×3×3 = 36. N characters are simply encoded as the values 0–9. Only the value 9 requires a leading 3. Z characters use the full 36 combinations representable by 3 bars. The values 0–25 encode the letters A–Z, and 26–35 encode the digits 0–9. A characters have a somewhat peculiar encoding. They can also be decoded as three base-3 digits (a leading 3 is never used), with the values 2–26 mostly encoding A–Y. Exceptions are that 0 encodes M, 1 encodes H, 9 encodes Z (rather than H), and code 14 is not used (rather than encoding M). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「PostBar」の詳細全文を読む スポンサード リンク
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