  The decoupling limit of the D1-D5 system compactified on T^4\times S^1 has a
rich spectrum of U(1) charged excitations. Even though these states are not BPS
in the limit, BPS considerations determine the mass and the semiclassical
entropy for a given charge vector. The dependence of the mass formula on the
compactification moduli situates the symmetric orbifold Sym^N(T^4) x T^4
conformal field theory in the moduli space. A detailed analysis of the global
identifications of the moduli space yields a picture of multiple weak-coupling
limits - one for each factorization of N into D1 and D5 charges d1 and d5=N/d1
- joined through regions of strong coupling in the CFT moduli space.
