byte data type
The xs:byte data type represents an integer that is less than or equal to 127 and greater than or equal to -128. Derived from the xs:short data type.
The lexical form of xs:byte is an optional sign that is
followed by a finite-length sequence of decimal digits. If the sign
is omitted, a positive sign (+) is assumed. The following numbers
are valid examples of this data type: -1, 0, 126, and +100
.