This dispute is between Opal Telecom Limited (Opal) and British Telecommunications plc (BT). It relates to the manner in which non-BT originated, fixed line calls to geographic telephone numbers, which BT has ported-out to Opal, are transited across BTs network and handed over to Opal, and how related costs are borne. Opal wants BT to hand over these calls at the relevant BT Digital Local Exchange (DLE) where Opal is interconnected with BTs network and submitted a Statement of Requirements (SOR) to BT to this effect. While BT confirmed that a DLE Handover solution was technically possible, it stated that this could only be offered to Opal provided that Opal paid for the system development costs necessary to enable BT to implement DLE Handover. Opal rejected BTs proposal in response to the SOR on the grounds that BT should be required to cover the costs of providing DLE Handover pursuant to its obligations under General Condition 18 (GC 18) of the General Conditions of Entitlement (the General Conditions) relating to number portability. As the parties have been unable to reach agreement on this, Opal brought this dispute to Ofcom for resolution.