  We give an effective algorithm to determine the endomorphism ring of a
Drinfeld module, both over its field of definition and over a separable or
algebraic closure thereof. Using previous results we deduce an effective
description of the image of the adelic Galois representation associated to the
Drinfeld module, up to commensurability. We also give an effective algorithm to
decide whether two Drinfeld modules are isogenous, again both over their field
of definition and over a separable or algebraic closure thereof.
