The Yellow cable system (also known as Atlantic Crossing 2,  AC-2) is a 6,400 km trans-Atlantic submarine cable system linking the USA and the UK.

The AC-2 was put into service in September 2000, with an initial design capacity of 320 Gbps on 4 fiber pairs.

In May 1999, Level3 decided to lay the Yellow transatlantic cable system, with 4 fiber pairs.  At that time, demand was heavily outstripping supply. Other cables in place at the time included AC1, TAT 12/13. The construction and maintenance agreement for TAT14 had been signed, but the RFS date was not scheduled until late 2000. In 1999, long term indefeasible rights of use (IRU) for STM1/OC3 was priced at approximately $3 million and above. Coupled with this, the cost of ongoing operations and maintenance was in the region of $150,000 per year per STM1/OC3. The initial cost was relatively high for a single company, therefore the decision was taken to defray the large upfront project cost by entering into a strategic partnership. 

Level3 signed a coconstruction agreement with Global Crossing which took two out of the four fiber pairs on the Yellow cable system. Operating in this environment meant Level 3 already recouped half the cost for Yellow before construction even began. Global Crossing marketed their two fiber pairs of the Yellow cable system as Atlantic Crossing 2, or AC-2. Global Crossing's private Atlantic Crossing 1 (AC-1) cable system was ready for service in 1999.

Level3 owned two fiber pairs and signed an IRU agreement on a fiber pair with Viatel. In this way, Level3 recovered approximately 70% of capital costs on the Yellow cable system before the system even entered service.

The AC-2/Yellow cable lands at Level3's cable landing station at Bellport, Long Island, NY, and Global Crossing's cable landing station at Bude, the UK.

After the acquisition of Global Crossing by Level3 and the followed acquistion of Level3 by Century Link, AC-1 and AC-2/Yellow are now wholly owned by Century Link.