Deutsche Telekom has joined Intel in investing in VoIP firm Jajah through its investment arm T-Online Venture Fund, reports the BBC. Around the world fixed-line revenues are falling, often because people move to a mobile-only phone life or use VoIP service over their broadband connection. Obviously DT has a strong mobile business going, this investment is an effort to stem losses to the VoIP segment. AP notes that Jajah is a good investment for carriers because ?the existence of Jajah encourages people to keep their fixed lines?, according to Jajah CEO Trevor Healy. Jajah pays to connect calls to carriers, and as part of the deal will pay reduced fees to Deutsche companies. It also works on mobiles. ?Deutsche Telekom says it has now started embedding Jajah into its web properties and that it expects to offer its calling services to consumers and businesses in the future.? It has also launched a WiFi smartphone in the US with VoIP capabilities.