Generic Requirements for Indoor Fiber Distribution Hubs (FDHs)

GR-3123-CORE testing specifies requirements to qualify indoor fiber distribution hubs (FDH). An indoor FDH can be installed on a customer premise in a basement or “telephone room”. This GR considers the FDH to be an outside plant (OSP) closure for use in an uncontrolled environment. Some example of test include:

• Vertical Drop test: Tests the FDH’s structural integrity after dropped from a height.
• Weather Tightness test:: Exposes the FDH to wind driven dust particles.

When an FDH is installed indoors, it must be able to withstand any external interference to the proper operation of the internal components. Such interference can range from water spray (sprays an FDH with water from a pressurized source per UL 497) to sudden vibration (earthquakes). GR-3123 testing mimics plausible indoor environment(s) that would potentially disrupt the proper flow of the optical signal.