  A test-bench has been set up at the INFN Sezione di Bologna to optimise key
elements of the KM3NeT data acquisition system. A complete framework has been
built to simulate a full detection unit and test the optical network, time
synchronisation, and on-shore computing resources. A fundamental tool in the
test-setup is a customized electronic board: "the OctoPAES". Based on an Altera
MAX10 CPLD, it is designed to emulate in a realistic way the optical and
acoustic signals recorded by the underwater detectors. They allow to test in
extreme conditions the acquisition system and validate its performance with
realistic data. If properly configured, the optical data provided by the
OctoPAES can be combined to emulate the signals of a through-going muon or
other calibration events. In this contribution the OctoPAES boards and some of
their use cases at the test-bench are presented.
