Syntax
set aString = aBlob.transcodeToString(charset);
SemanticsThe operation transcodes blobs encoded with a given character set into an internal string. The returned string is always UTF-8 encoded.
SubstitutablesaStringCan be any variable or object attribute having type String. 
aBlobCan be any variable or object attribute having type Blob.
charsetSpecifies the encoding of the characters stored in aBlob.
charset can be any variable or object attribute having type String and denoting a valid character set (e.g. UTF-8, ISO-8859-1, etc.). A list of supported character sets can be found in Charset Definitions.
Examples

This example transforms a blob that contains ISO-8859-1 encoded characters into an internal string:

set aString = aBlob.transcodeToString("ISO-8859-1");

Example File (Builder project Basic Modeling/Data):

<your example path>\Basic Modeling\Data\uml\transcoding.xml

Figure: Operation transcodeToString()