In this work, LLE data at different temperatures have been correlated for 30 binary systems that presented different miscibility behaviour: 15 upper critical solution temperature (UCST), 5 critical solution temperature (LCST) and 10 closed loop LLE region systems. The NRTL model along with an expression frequently used in literature for the temperature dependence in the binary interaction has allowed an acceptable fitting of all the systems. The parameters obtained have been validated by both the inspection of the Gibbs energy of mixing function regarding the fulfilment of the Gibbs common tangent equilibrium condition, and also the stability of the solution to avoid possible metastable equilibrium solutions. The critical solution temperatures have been calculated by extrapolation using the NRTL parameters obtained for all selected binary systems.Moreover, the NRTL parameter values have been analysed using some proposed representations that also include the boundary curve between miscible (L) and partially miscible (LLE) regions. These graphical representations are useful because they show the parameter value requirements to reproduce UCST, LCST or closed loop behaviours.