  Superconducting circuits incorporating Josephson tunnel junctions are widely
used for fundamental research as well as for applications in fields such as
quantum information and magnetometry. The quantum coherent nature of Josephson
junctions makes them especially suitable for metrology applications. Josephson
junctions suffice to form two sides of the quantum metrology triangle, relating
frequency to either voltage or current, but not its base, which directly links
voltage to current. We propose a five Josephson tunnel junction circuit in
which simultaneous pumping of flux and charge results in quantized
transconductance in units $4e^2/h = 2e/\Phi_0$, the ratio between the Cooper
pair charge and the flux quantum. The Josephson quantized Hall conductance
device (JHD) is explained in terms of intertwined Cooper pair pumps driven by
the AC Josephson effect. We discuss the experimental implementation as well as
optimal configuration of external parameters and possible sources of error. JHD
has a rich topological structure and demonstrates that Josephson tunnel
junctions are universal, capable of interrelating frequency, voltage, and
current via fundamental constants.
