A binary counter circuit in the extended phase-mode logic (EPL) family is presented. The EPL family utilizes a single flux quantum as an information bit carrier. Numerical simulations show that a binary counter circuit with a Josephson critical current density of 1 kA/cm2 can operate up to a 30 GHz input signal. The circuit has been fabricated using Nb/AlOx/Nb Josephson junction technology. New interface circuits are employed in the fabricated chip. A low speed test result shows the correct operation of the binary counter.