  The recently formulated Two Oscillator (TO) model interprets the lowest of
the kilohertz frequencies of the twin peak quasi-periodic oscillations in X
-ray binaries as the Keplerian frequency nu_K. The high twin frequency nu_h in
this model holds the upper hybrid frequency relation to the rotational
frequency of the neutron star's magnetosphere Omega: nu_h^2=nu_K^2+
4(Omega/2pi)^2. The vector Omega is assumed to have an angle delta with the
normal to the disk. The first oscillator in the TO model allows one to
interpret the horizontal branch observed below 100 Hz as the lower mode of the
Keplerian oscillator under the influence of the Coriolis force, with frequency
nu_L being dependent on nu_h, nu_K and delta. For some stars such as 4U
0614+09, Sco X-1 and 4U 1702-42, nu_h, nu_K and nu_L have been observed
simultaneously providing the opportunity to check the central prediction of the
TO model: the constancy of delta for a particular source. Given the
considerable variation of each of these three frequencies, the existence of an
observational invariant with a clear physical interpretation as a global
parameter of the neutron star magnetosphere is an important test of the TO
model. Using the results of recent observations of 4U 0614+09 we verify the
existence of this invariant and determine the angle delta=15^o.6+/- 0.^o5 for
this star. The second oscillator in the model deals with a radial (presumably
sound) oscillation and diffuse process in the viscous layer surrounding the
neutron star. Our analysis of the viscous oscillation frequency nu_V and the
break frequency nu_b of the diffusion shows that the spin value of the inner
boundary of the transition layer for 4U 0614+09 is at least two times more than
values for 4U 1728-34 and Sco X-1.
