Skip to content

GR-3120: Fiber Optic Connectors and Adapters

For Users, Manufacturers and Suppliers of HFOCs

STW 3IN1 Hybrid Connectors

GR-3120, Issue 2, Generic Requirements for Hardened Fiber Optic Connectors (HFOCs) and Hardened Fiber Optic Adapters (HFOAs)

GR-3120 contains requirements for Hardened Fiber Optic Connectors (HFOCs) and Hardened Fiber Optic Adapters (HFOAs). These are passive telecommunications components used in an Outside Plant (OSP) environment. They provide drop connections to customers from fiber distribution networks. These components may be provided in pedestal closures, aerial and buried closures and terminals, or equipment located at customer premises such as a Fiber Distribution Hub (FDH) or an Optical Network Terminal or Termination (ONT) unit.

These connectors, which are field-mateable, and hardened for use in the outside plant (OSP), are needed to support Fiber to the Premises (FTTP) deployment and service offerings. Issue 2 of GR-3120:

  • Includes updates to various requirements and test procedures, and contains a new test program matrix making the document clearer and easier to use
  • Contains new criteria for mechanical performance, chemical resistance, endface geometry, thermal expansion, and more
  • Aligns with GR-326, Generic Requirements for Singlemode Optical Connectors and Jumper Assemblies, and GR-771, Generic Requirements for Fiber Optic Splice Closures


The requirements in GR-3120, Issue 2, have been accepted as an industry standard, thus saving you considerable expense in formulating your own specifications and work plans. This GR also includes an Issue List Reports (ILR) that details open or closed technical issues in the main document.