Arcor is the former name of the fixed phone line and Internet business of Vodafone D2 GmbH, a German subsidiary of telecommunications company Vodafone. It is the second-largest provider of fixed phone lines in Germany after Deutsche Telekom. Its name changed on 1 August 2009 after Vodafone completed acquisition of the company. Its headquarters were in Eschborn near Frankfurt. It is one of the few telecommunications companies in Germany to operate an ISDN network that is independent of the incumbent provider Deutsche Telekom.
In 2008 Vodafone Germany had 2.1 million ADSL customers and 1.1 million ISDN customers.[citation needed] Arcor was the first German telecommunications provider to offer a flat rate tariff for ISDN phone lines.[citation needed]