What does South Netcom mean by North Telecom?

In 2008, China Unicom and China Netcom merged to form the current Unicom.

This sentence describes the advantageous areas divided by China Telecom and China Unicom. At that time, the Yellow River was the boundary between the north and the south, and the northern provinces and cities 10, Beijing, Tianjin, Hebei, Henan, Shandong, Shanxi, Heilongjiang, Jilin, Liaoning and Inner Mongolia were the dominant regions of China Netcom, while the other 2 1 provinces and cities were the strong regions of China Telecom. This north-south refers to the division of the Yellow River.