A case study of the dayside cusp/cleft region during an interval of stationary magnetospheric convection (SMC) on November, 24, 1981 is presented, based on detailed measurements made by the AUREOL-3 satellite. Layered small-scale field-aligned current sheets, or loops, superimposed to a narrow V-shaped ion dispersion structure, were observed just equatorward from the region of the &quot;cusp proper&quot;. The equatorward sheet was accompanied by a very intense and short (less than 1 s) ion intensity spike at 100 eV. No major differences were noted of the characteristics of the LLBL, or &quot;boundary cusp&quot;, and plasma mantle precipitation during this SMC period from those typical of the cusp/cleft region for similar IMF conditions. Simultaneous NOAA-6 and NOAA-7 measurements described in Despirak <i>et al</i>. were used to estimate the average extent of the &quot;cusp proper&quot; (defined by dispersed precipitating ions with the energy flux exceeding 10^-3 erg cm^-2 s^-1) during the SMC period, as ~0.73° ILAT width, 2.6-3.4 h in MLT, and thus the recently merged magnetic flux, 0.54-0.70 × 10⁷ Wb. This, together with the average drift velocity across the cusp at the convection throat, ~0.5 km s^-1, allowed to evaluate the cusp merging contribution to the total cross-polar cap potential difference, ~33.8-43.8 kV. It amounts to a quite significant part of the total cross-polar cap potential difference evaluated from other data. A &quot;shutter&quot; scenario is suggested for the ion beam injection/penetration through the stagnant plasma region in the outer cusp to explain the pulsating nature of the particle injections in the low- and medium-altitude cusp region.<br><br><b>Key words.</b> Magnetospheric physics (current systems; magnetopause · cusp · and boundary layers; solar wind-magnetosphere interactions).