  We present an analysis of \emph{VI} CCD time-series photometry of the Oo II
type globular cluster M92. The variable star population of the cluster is
studied with the aim of revising their classifications, identifications,
frequency spectra and to select indicators of the parental cluster metallicity
and distance. The Fourier decomposition of RR Lyrae light curves lead to the
estimation of mean [Fe/H]$_{\rm spec}=-2.20\pm 0.18$, and distance of
$8.3\pm0.2$ kpc. Four new variables are reported; one RRd (V40), a multimode SX
Phe (V41), a SR (V42) and one RRc (F1) that is most likely not a cluster
member. The AC nature of V7 is confirmed. The double mode nature of the RRc
star V11 is not confirmed and its amplitude modulations are most likely due to
the Blazhko effect. Two modes are found in the known RRc variable V13. It is
argued that the variable V30, previously classified as RRab is, in fact, an BL
Her-type star not belonging to the cluster. Making use of the $Gaia$-DR2 proper
motions, we identified 5012 stars in the field of the cluster, that are very
likely cluster members, and for which we possess photometry, enabling the
production of a refined Colour-Magnitude Diagram. This also allowed us to
identify a few variable stars that do not belong to the cluster. The RR Lyrae
pulsation modes on the HB are cleanly separated by the first overtone red edge,
a common feature in all Oo II type clusters.
