A readout box prototype for the CMS Hadron Forward calorimeter upgrade
was built and tested in the CERN H2 beamline. The prototype was designed
to enable simultaneous tests of different readout options for the four
anode upgrade PMTs, new front-end electronics design and new cabling.
The response of the PMTs with different readout options was uniform and
the background response was minimal. Multi-channel readout options
further enhanced the background elimination. Passing all the electronic,
mechanical and physics tests, the readout box proved to be capable of
providing the forward hadron calorimeter operational requirements in the
upgrade era