The spectrum of an oriented AA′XX′ spin system can be analysed to give only the parameters δAX,JAA′,TAA′zz,JXX′,TXX′zzand the combinations (JAX+JAX′+ 2TAXzz+ 2TAX′zz) and (JAX-JAX′+ 2TAXzz- 2TAX′zz). By controlled, slow sample rotation it is possible to determine all these parameters separately, and some of their relative signs. Application of this technique tocis-difluoroethylene confirms the signs of the coupling constants determined by Baldeschwieleret al.The dipolar couplings forcis-difluoroethylene are compared with values calculated assuming the geometry as determined from microwave spectroscopy and including the effects of harmonic vibrations.