  String theory on 2-d charged black holes corresponding to (SL(2)xU(1)_L)/U(1)
exact asymmetric quotient CFTs are investigated. These backgrounds can be
embedded, in particular, in a two dimensional heterotic string. In the extremal
case, the quotient CFT description captures the near horizon physics, and is
equivalent to strings in AdS_2 with a gauge field. Such string vacua possess an
infinite space-time Virasoro symmetry, and hence enhancement of global
space-time Lie symmetries to affine symmetries, in agreement with the
conjectured AdS_2/CFT_1 correspondence. We argue that the entropy of these 2-d
black holes in string theory is compatible with semi-classical results, and
show that in perturbative computations part of an incoming flux is absorbed by
the black hole. Moreover, on the way we find evidence that the 2-d heterotic
string is closely related to the N=(2,1) string, and conjecture that they are
dual.
