It is well established that the order parameter symmetry in the hole doped
high-temperature superconductors (HTS) is of d-wave type. In contrast, ther
e is growing experimental evidence for a s-wave type symmetry in the electr
on doped cuprate superconductors. We present tunneling spectra and measurem
ents of the London penetration depth, both supporting strongly the s-wave s
cenario for the electron doped HTS [1]. The absence of Andreev bound states
in the tunneling spectra indicates a state without sign change of the pair
potential, and the absence of low energy excitations as revealed by the Lo
ndon penetration depth measurements suggests a gapped state. Based on these
experiments, for the materials (Nd/Pr)(1.35)Ce0.15CuO4-y an about isotropi
c s-wave symmetry seems more likely than a strongly anisotropic s-wave symm
etry. For the Nd compound we observe anomalous low temperature behavior due
to the Nd3+ magnetic moments.