RST300-S is a standard 19-inch, 1U rack frame intended for desktop intercom configurations. It provides a short-format chassis compatible with CST38, CSR50-D and CST50-D assemblies, enabling compact rack installations for legacy systems. The product is listed as a discontinued accessory; the page does not publish power, weight, or depth data, and no accessories are shown. Its 19-inch footprint and 1U height align with conventional rack mounting practices.