SIEMENS RAISES STAKE IN TELECOM PLUS OF U.S. Siemens AG's <SIEG.F> fully-owned subsidiary Siemens Informations Systems Inc. Has raised its stake in Telecom Plus Communications Inc. By 65 pct to 100 pct, a Siemens spokesman said. He added that Telecom Plus Communications was the largest independent supplier of telephone exchange systems in the U.S. And had achieved a turnover of 234 mln dlrs in 1986. The stake had been acquired from Telecom Plus International Inc. The spokesman declined to comment on U.S. Newspaper reports that the purchase price of the remaining stake totalled 173 mln dlrs.