  The Mu2e calorimeter will employ Readout Units, each made of two Silicon
Photomultipliers arrays and two Front End Electronics boards. To calibrate
them, we have designed, assembled and put in operation an automated Quality
Control (QC) station. Gain, collected charge and photon detection efficiency
are evaluated for each unit. In this paper, the QC Station is presented, in its
hardware and software aspects, summarizing also the tests performed on the ROUs
and the first measurement results.
