The rovibronic levels for the X(2)Sigma(+), A(2)Pi electronic system of C2H, C2D and all C-13 substituted isotopomers are calculated using a recently developed variational method [Carter et al., Mol. Phys. 98, 1967 (2000)] and high level ab initio diabatic potential energy surfaces. Energies, rotational constants and spin-orbit splittings of all levels of Sigma, Pi, Delta, Phi symmetry are reported up to 6400 cm(-1) for C2H and up to 5500 cm(-1) for C2D. Computed energies of Sigma, Pi levels up to 10000 cm(-1) are also reported for all C-13 substituted isotopomers. Experimental data are reviewed in the light of the present results. (C) 2003 American Institute of Physics.