Dark Fibre X (DFX)

DFX is a new fibre product from Openreach which allows customers to design and build connectivity services and solutions. The product is designed to provide backhaul connectivity on routes between qualifying BT Exchanges and is available on the Openreach strategic EMP platform.

Geographic coverage

  • Soft Launch: Phased geographic roll out from 8th August – 31st Dec 2019 (for more details see supporting Product Description)
  • Full Launch: Available on a national basis from 1st January 2020.


Openreach Dark Fibre X service offers an uncontended, unmonitored, unlit optical path over an end to end maximum route distance of 86km between two qualifying BT Exchange sites. This will be a passive service and no equipment will be provided to light the fibre, hence the reference to ‘dark fibre’ in the product title.

Product options and scope

DFX is available on routes between qualifying BT Exchanges as set out in the DFX Product Description at Section 3 and the contract.

The service will be available with two variants, it can be ordered as either a single fibre or fibre pair option, so depending on the overall solution that customers are planning to operate they can choose the product variant that best suits their needs.


  • 8th August 2019 - Soft launch of DFX and publication of the DFX Reference Offer plus supporting documentation
  • 1st January 2020 - Full launch and publication of a revised DFX Reference Offer plus supporting documentation

Customers should note that Openreach is still reviewing Ofcom's Final Statement including its final decision to require BT to offer a dark fibre product and considering all legal options available to it. Customers considering investing in dark fibre product from Openreach in line with the Dark Fibre Remedy do so at their own risk.

The information contained within this site, including all documentation, is confidential and must not be shared externally by the Communications Provider. Individuals within the Communications Provider organisation must be made aware of the content of the wording of this disclaimer when reviewing documentation.


DFX Final Reference Offer

In line with Ofcom's Final Business Connectivity Market Review published on 28th June 2019, Openreach is required to publish a final reference offer for its Dark Fibre X (DFX) product by 12th August 2019.This can be found at:

Customer zone

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DFX State Aid Qualifying Infrastructure

Where Openreach has utilised public funding to enhance its existing infrastructure to roll out exchange to exchange fibre in specific geographic locations, CPs can apply for access using a DFX supplemental agreement.