  The determination of the neutrino mass is an open issue in modern particle
physics and astrophysics. The direct mass measurement is the only
theory-unrelated experimental tool capable to probe such quantity. The HOLMES
experiment aims to measure the end-point energy of the electron capture (EC)
decay of $^{163}$Ho with a statistical sensitivity on the neutrino mass as low
as $\sim 1$ eV/c$^2$. In order to acquire the large needed statistics, by
keeping the pile-up contribution as low as possible, 1024 transition edge
sensors (TESs) with high energy and time resolutions will be employed.
Microcalorimeter and bolometer arrays based on transition edge sensor with
thousands of pixels are under development for several space-based and
ground-based applications, including astrophysics, nuclear and particle
physics, and materials science. The common necessary challenge is to develop
pratical multiplexing techniques in order to simplify the cryogenics and
readout systems. Despite the various multiplexing variants which are being
developed have been successful, new approaches are needed to enable scaling to
larger pixel counts and faster sensors, as requested for HOLMES, reducing also
the cost and complexity of readout. A very novel technique that meets all of
these requirements is based on superconducting microwave resonators coupled to
radio-frequency Superconducting Quantum Interference Devices, in which the the
changes in the TES input current is tranduced to a change in phase of a
microwave signal. In this work we introduce the basics of this technique, the
design and development of the first two-channel read out system and its
performances with the first TES detectors specifically designed for HOLMES. In
the last part we explain how to extend this approach scaling to 1024 pixels.
