What does seven countries and eight systems mean?

"Seven countries and eight series" refers to the sum of eight models in China's communication market in the 1980s. Among them, Japanese NEC and Fujitsu respectively occupied two systems, coming from seven countries:

NEC and Fujitsu in Japan, Lucent in the United States, Ericsson in Sweden, Siemens in Germany, BTM in Belgium and Alcatel in France.