  Electrical characteristics $(I(eV), dV/dI(eV), d^{2}V/dI^{2}(eV))$ are
studied comprehensively for pressed submicron point contacts between fresh
fractures of LaSrCuO ceramic pellets and a normal metal (Cu). Point contacts
(PC) with the direct-type conductivity are investigated, which are
characterized by a considerable excess current due to Andreev reflection of
quasiparticles at an NS boundary of high transparency. Basic requirements for
point contacts suitable for PC measurements are formulated. The models of
investigated point contacts permitting the interpretation of the observed
characteristics are considered. The results of measurement of the energy gap
reveal that LaSrCuO is a superconductor with a strong coupling since the
maximum value of the ratio $2\Delta/kT\simeq 11$. It is found that
superconducting properties may vary appreciably over distances of several tens
of angstroms, resulting in some cases in the simultaneous emergence of two gaps
corresponding to two critical temperatures. The $dV/dI(eV)$ and
$d^{2}V/dI^{2}(eV)$ curves display some high-intensity singularities whose
position on the eV-axis is practically independent of temperature and
correlates with the phonon spectrum obtained in neutron scattering experiments.
This points to a strong electron-phonon interaction in LaSrCuO.
