BT Global Services is the enterprise and public sector division of leading UK telecommunications carrier BT Group. It provides wired voice and data telecom and networked IT services to multinational corporate customers in more than 170 countries, but the UK government is its top client. BT Global Services operates a leading European digital network that includes transatlantic fiber-optic connections to the Americas and its own multiservice platform. The unit also provides managed network security (including BT Managed Security in the US), data center services, and call centers for its customers. BT Global Services is the largest of BT Group's four main segments, accounting for 40% of total sales.