Deutsche Telekom - FT.com If only Deutsche Telekom had been able to take AT&T's call last year. Now, with the line dead on the proposed $39bn sale of its T-Mobile USA business to the American behemoth, the German company is going it alone. But service, for investors, has broken up.Announcing full-year results on Thursday, domestic revenues - about half the business - were down 4 per cent at €24bn, partly because of pressure on mobile termination rates. Underlying margins, however, improved. And the group overall was ahead on cost-cutting, squeezing out €4.5bn by year-end compared with a targeted €4.2bn by 2012. That pushed margins (at the earnings before interest, tax, depreciation and amortisation level) slightly higher to 32 per cent.That was the good news. Against this, there were very slight misses on ebitda, at €18.7bn, and free cash flow. And Deutsche Telekom took €3.3bn of goodwill and asset writedowns in the US and Greece, offsetting compensation received from AT&T after the deal hit regulatory buffers. Worse, investors are being warned to brace for an uninspiring year ahead as economic and regulatory pressures persist. Cash flow and ebitda, on company forecasts, could dip further in 2012.But the new crackle on the line is the US situation. In the short term, Deutsche Telekom is upping investment in T-Mobile USA - an extra $1.4bn over two years - so that it can begin offering services on the new LTE communications standard, and also planning a brand relaunch. But the US business is inherently sub-scale and spectrum-constrained. So until more clarity on the vague but promised "longer-term solution" emerges Deutsche Telekom's share price - moribund for six months - is unlikely to revive. In contrast to some peers, the group is holding its dividend although timing of a share buy-back is less clear. That, though, is not the call which really matters..E-mail the Lex team in confidence at lex@ft.com