IDMAR is an Underwater, Multidisciplinary Infrastructure for Research in the abyssal of Mediter-
ranean Sea (off Sicily south-eastern coast), integrating innovative sensors for a real-time study in
a submarine environment. One of the main IDMAR use cases is ARCA, the Cherenkov detector
being built by the KM3 Neutrino Telescope (KM3NeT) Collaboration for the study of cosmic
neutrinos at TeV-PeV energies [1]. The Junction Box (JB) is a key component of IDMAR: it
receives the electro-optical signal carried out from onshore through the Main Electric-Optic Cable
and distributes this signal to the underwater user experiments, for instance the KM3NeT Detection
Units (DUs). Aside the electronic boards needed to manage the electro-optical signals, each
JB hosts calibration instruments for time synchronisation and acoustic positioning of submarine
observatories: a laser beacon, an acoustic beacon and a hydrophone. It is here described the JB
Slow Control (JB-SC), the three-tier software layer that enables remote control of the offshore JB
equipment, also receiving JB telemetry data, for the monitoring of the hardware and the measure-
ment of its performance, to eventually prevent hardware failures. A consistent part of this software
has been developed on purpose, relying on open source components: this contribution describes
the architectural choices, and the methods adopted for combining the open source components in
order to achieve the monitoring and control purposes. Finally, an outlook to the future evolution
of the software will be given, taking into account the expansion of JB use cases, following the
increase of the KM3NeT detector size.