FDX 20 DIN-rail fibre-optic boxes terminate fibre-optic cables in field cabinets without a separate rack. The metal enclosure is 40 mm wide, 130 mm high and 115 mm deep, is rated IP20 according to IEC 60529, and accommodates six modular sockets, i.e. six LC duplex connectors for 12 fibres. The railway catalogue includes versions from 6 to 12 duplex connections. Operating temperature depends on the version: FOC-FDX20-PP-LCD6-OM2-PT9 operates from −25 °C to 70 °C, while the single-mode FOC-FDX20-PP-LCD6-OSP-PT9 and splitter FOC-FDX20-PP-LCD6/LCD6-OSP operate from −40 °C to 85 °C. The latter range determines suitability for unheated wayside cabinets. Installation temperature is narrower than operating temperature: 0 °C to 50 °C, and 0 °C to 55 °C for the splitter.
The box is the transition point between the field level-cables laid underground over distances of kilometres-and active network components such as switches, routers and converters. The housing has two parts, with cable entry through a gland from the top or bottom; it transfers loads from the buried cable and secures its strength members, while a splice shelf with cassette maintains the fibre bend radius inside. Zirconia ceramic ferrules are 1.25 mm in diameter, and connectors withstand at least 500 mating cycles. DIN-rail mounting places the box next to other field-cabinet equipment, distinguishing it from the 19-inch rack version that gathers a larger number of links in a telecommunications cabinet.
Two construction variants are available. In the splice version, incoming cable fibres are fusion-spliced to 900 µm pigtails installed inside the enclosure-in multimode OM2 50/125 µm or single-mode versions. The single-mode version datasheet specifies bend-insensitive G.657 fibre, allowing routing at tight radii inside the 40 mm-wide housing. The splitter version contains no pigtails and accepts factory-terminated or field-terminated cables; pigtails are ordered separately. The catalogue includes LC, SC, ST and LSH connectors and OM1, OM2, OM3, OM4 and OS2 fibres in PC or APC versions, with polymer or metal couplers. Datasheets confirm housing flammability class V0 according to UL 94. Compliance with DIN EN 45545-2 for fire protection is explicitly declared in the product-list heading for DIN-rail versions-unlike the 19-inch rack versions, where this note is absent. Confirmation for a specific item is provided by the manufacturer’s railway-application declaration downloadable from the manufacturer’s shop for the relevant catalogue number.
