ZTE, the Chinese telecommunications giant that was on the brink of collapse after being hit with tough penalties by the Trump administration, has become a linchpin of trade relations between the United States and China. On Thursday, Wilbur Ross, the commerce secretary, said the administration had reached a deal to lift restrictions imposed on ZTE after it was found to have violated American sanctions related to doing business with countries like Iran and North Korea. ZTE’s fate has been at the center of a broader dispute between China and the United States, and the deal announced on Thursday could inflame a battle with Congress over national security interests.

Here’s what you need to know.

What Is ZTE?

Zhongxing Telecommunications Equipment, known as ZTE, makes cheap smartphones that are mostly sold in developing countries, though it also sells them in the United States.

But ZTE is one of two Chinese companies — Huawei is the other — that sell equipment for cellular networks. It has about 75,000 employees and says it does business in more than 160 countries.

That makes it an important geopolitical pawn for Beijing, both as an innovator and as a builder of state-funded projects overseas. If China wants to improve ties with a government in the developing world, it often offers loans that can be used to set a ZTE-powered cellular network.