  I derive a smooth and global Kruskal-Szekeres coordinate chart for the
maximal extension of the non-extremal Reissner-Nordstr\"om geometry that
provides a generalization to the standard inner and outer Kruskal-Szekeres
coordinates. The Kruskal-Szekeres diagram associated to this coordinate chart,
whose existence is an interesting fact in and on itself, provides a simple
alternative with a transparent physical interpretation to the conformal diagram
of the spacetime.
