L M Ericsson Telefon AB announced yesterday that it has opened a factory to make cellular telephones and assemble AXE digital exchanges in Nanjing, China. The plant is owned by a joint venture in which the Swedish company is just the majority shareholder. Chinese electronics firm Panda is the next largest shareholder in Nanjing Ericsson Communications Ltd, and the firm starts life with 70 employees, to grow to 500 at full production. Ericsson has three other joint ventures in China and another plant is soon to open in Guangzhou; sales in China have doubled in the past year and is now the fifth largest market for Ericsson, which now employs 500 people in the country.