RST22-S is a 19-inch, 3U rack frame for Wisycom UHF full‑duplex multichannel systems. It is eight modules wide and can be populated with up to seven RF modules plus a PSS26 or PSS23 mains power supply. Compatible modules include FAS16, CSR50, CST36 and CST50. The unit is provided as a custom, discontinued frame suitable for fixed installations, with options for iso‑frequency and diversity configurations.