The Presentation Layer

The Presentation Layer
The Presentation layer does what you might think it does: It changes the look, or presentation, of the data from the lower layers into a format that the upper-layer processes can work with.
Among other services, the Presentation layer deals with encryption, data compression, and network redirectors. 
      In addition, the Presentation layer deals with character-set translation. Not all computer systems use the same table to convert binary numbers into text. Most standard computer systems use the American Standard Code for Information Interchange (ASCII). Mainframe computers (and some IBM networking systems) use the Extended Binary Coded Decimal Interchange Code (EBCDIC) and Unicode, which is popular on the Internet as one character set that assigns a
unique number to every character regardless of the language or the operating system used to display the character. The three are totally different. Protocols at the Presentation layer can translate
between the three.