  In this paper, we discuss the simple current orbifold of a rational Narain
CFT (Narain RCFT). This is a method of constructing other rational CFTs from a
given rational CFT, by ``orbifolding'' the global symmetry formed by a
particular primary fields (called the simple current). Our main result is that
a Narain RCFT satisfying certain conditions can be described in the form of a
simple current orbifold of another Narain RCFT, and we have shown how the
discrete torsion in taking that orbifold is obtained. Additionally, the
partition function can be considered a simple current orbifold with discrete
torsion, which is determined by the lattice and the B-field. We establish that
the partition function can be expressed as a polynomial, with the variables
substituted by certain q-series. In a specific scenario, this polynomial
corresponds to the weight enumerator polynomial of an error-correcting code.
Using this correspondence to the code theory, we can relate the B-field, the
discrete torsion, and the B-form to each other.
