  We introduce a new type of equivalence between blocks of finite group
algebras called a strong isotypy. A strong isotypy is equivalent to a
$p$-permutation equivalence and restricts to an isotypy in the sense of
Brou\'{e}. To prove these results we first establish that the group
$T_{\mathcal{O}}(B)$ of trivial source $B$-modules, where $B$ is a block of a
finite group algebra, is isomorphic to groups of ``coherent character tuples.''
This provides a refinement of work by Boltje and Carman which characterizes the
ring $T_{\mathcal{O}}(G)$ of trivial source $\mathcal{O}G$-modules, where $G$
is a finite group, in terms of coherent character tuples.
