The neutron-deficient isotopes 254,255 Rf were produced in the fusion-evaporation reaction 50 Ti + 206 Pb at the gas-filled recoil separator TASCA. Decay properties of these nuclei were investigated by applying fast digital electronics. A search for isomeric states in both isotopes was performed by using the accompanying conversion electron emissions. Isomeric states with half-lives of 4(1) μs and >30 μs were measured for 254 Rf and 255 Rf, respectively, which confirm the findings at different separators. The present experimental results demonstrate the great potential of fast digital electronics for measurements of isomeric states in the heaviest nuclei, which are only producible in small quantities.