A classical planar cable model has been presented in the Irvine textbook and is being used, for example, for the modeling of cable-driven parallel robot. It provides 2 equations involving parameters of the cable material, namely its Young modulus and its linear density, assumed here to be known, and 5 physical parameters namely the coordinates of one cable end-point B, the horizontal and vertical components of the force exerted at B and the length at rest of the cable. This model is extensively used in the modeling of devices where cables are involved (e.g the kinematics of cable-driven parallel robots) and the model analysis requires to be able to solve very efficiently this 2-equations system when it has 1 or 2 unknowns. We consider various cases where n physical parameters are known and we investigate how the Irvine equations may be exploited to compute the 5 − n remaining parameters. In some cases where n < 3it is possible to determine a closed-form solution for this 5 − n parameters. But if n = 3 it appears that only a numerical approach may allow to get the 2 remaining parameters. We present here a generic algorithm based on a mix of neural networks and deterministic algorithms allows one to get exact solution in that case.