Ericsson had been selected by British cable operator ntl:Telewest as a technology and services partner to help with developments to its telephone network using VoIP technology, a company statement said.
The companies signed a five-year agreement, the statement also said.
The initial phase of the agreement involves helping build a residential VoIP service utilizing Ericsson's IMS platform, which has been installed and is undergoing testing ahead of launch.
Under the agreement, Ericsson will also be involved with upgrading ntl:Telewest's voice network from circuit-switched technology to IP using Ericsson's IP-based telephony softswitch solution.
No financial information was provided.