  St 2-22 is a relatively poorly studied S-type symbiotic system that belongs
to a small group of jet-producing systems as a result of disc accretion onto a
white dwarf fed by its red giant companion. The goal of this paper is to
analyse the nature and derive the basic parameters of St 2-22, and to follow
the jet evolution. Photometric monitoring for over 16 yrs and high-quality
spectroscopic data enabled us to shed new light on its nature. The
high-resolution SALT spectra and $V I_C$ photometry obtained during and between
the last two outbursts have been used to search for periodic changes, to derive
spectroscopic orbits of both system components, and to study the outburst and
jet evolution. We present the orbital and stellar parameters of the system
components. The orbital period is $P_{orb} = 918 \pm6^d$. The double-line
spectroscopic orbits indicate the mass ratio $q = M_{g} M_{h}^{-1} = 3.50
\pm0.53$, and the components masses $M_{g} \sin^3{i} \sim 2.35$ M$_{sun}$ and
$M_{h} \sin^3{i} \sim 0.67$ M$_{sun}$. The orbit shows significant
eccentricity, $e = 0.16 \pm0.07$. The orbital inclination is close to 70
degrees. During outbursts, accelerating and decelerating jets are observed with
changes in their radial velocity component in a range from $\sim 1500$ up to
nearly $1800$ km s$^{-1}$. St 2-22 turned out to be a classical symbiotic
system very similar to the precursor of the group - Z And.
