Countries such as Germany, the Netherlands, Spain and the UK will be the initial target areas for the latest flavour of DSL from US-based operator Efficient Networks.Symmetrical high-density digital subscriber line (SHDSL) technology promises data rates of 2.3Mbps over a single copper pair, as opposed to the 1.5Mbps of conventional DSL lines. Efficient Networks, recently acquired by Siemens AG, plans a June roll-out of SHDSL. Whereas SDSL is limited to availability within 18,000 feet of the central office, SHDSL can reach 20,000 feet from central office switches and with repeaters can extend that to a theoretical limit of 19 miles. Scott Bender, a spokesman at Efficient Network pointed out that SHDSL provides the bi-directional high-speed transfers that voice, video, virtual private networking and other high-bandwidth applications require. "SHDSL promises transmission speeds of 4.6Mbps for both uploads and downloads," Bender said. He also said now that a standard for SHDSL has been determined, "businesses will jump all over it". In addition to working with existing networks, the new SHDSL standard also conforms to The International Telecommunications Union recommendations. Efficient Networks plans to introduce a SHDSL Business Gateway in Europe this summer targeted at small and midsize businesses and enterprise branch offices. SHDSL is expected to catch on faster in Europe than in the US because of Europe's slow adoption of other versions of DSL such as SDSL and ADSL. The US rollout should be a quarter or two behind the European rollout, Bender said.