(1) Three types of discharges have been chosen for JET. Within each discharge type, an approximate 'Greek-Latin square' with respect to the variables B, n, P and q has been constructed. The following features have been chosen to characterize the discharge type: material limiter ('limiter') or magnetic limiter ('X-point'); additional heating by RF waves ('RF') or by neutral beams ('NBI'); discharge periods in L-mode or in H-mode; discharge periods with normal sawtooth oscillations or without sawtooth oscillations. The discharge types presented are:(a) X-point – H-mode – NBI – normal sawteeth;(b) Limiter – L-mode – NBI – normal sawteeth;(c) Limiter – L-mode – RF – normal sawteeth.