  A well--known fact in Spectral Graph Theory is the existence of pairs of
isospectral nonisomorphic graphs (known as PINGS). The work of A.J. Schwenk (in
1973) and of C. Godsil and B. McKay (in 1982) shed some light on the
explanation of the presence of isospectral graphs, and they gave routines to
construct PINGS. Here, we consider the Godsil-McKay--type routines developed
for graphs, whose adjacency matrices are $(0,1)$-matrices, to the level of
signed graphs, whose adjacency matrices allow the presence of $-1$'s. We show
that, with suitable adaption, such routines can be successfully ported to
signed graphs, and we can build pairs of cospectral switching nonisomorphic
signed graphs.
