Ericsson said Thursday that it will withdraw from the cable-modem business, selling its Lynchburg, Va.-based unit to Aastra Technologies of Ontario, Canada. Telecommunications equipment maker Ericsson entered the cable-modem market in early 1999 with its PipeRider brand. The Swedish company said it sold a total of 200,000 modems and gained a 3 percent world market share during that time. Aastra primarily makes phones and accessories. The company said in a statement that the deal will give it a stronger presence in the Internet access market. Aastra purchased Lucent Technologies' digital video business in October, which makes equipment that helps TV, cable and telecommunications operators transmit video signals.