# What is the Postcode?

Zielcode – Wikipedia

Destination code, address code, postcode or address code refers to the barcode that various postal companies print on letters and postcards. The destination code is applied to the item at the first mail centre it passes through. This enables faster machine forwarding and sorting.

## Encoding/Decoding

German Post uses two different types of coding, 5-bit coding and 4-bit coding. The table opposite shows the coding of each digit. Each bit of the code corresponds to a numerical value. The numerical values of the set bits of the code are added together, their sum is the number that has been decoded, whereby there is an exception in both encodings: In 5-bit coding, the sum (7+4)=11 represents the digit “zero”; in 4-bit coding, the sum (8+2)=10 represents the digit “seven”. This means that with 5-bit coding, exactly 2 bits are always set and 3 are not set and with 4-bit coding, a maximum of two bits are set and at least two are not set. 10 of the 11 such coding dash patterns are used, 8+4=12 is not used.