用户使用的电话机,键盘上通常都设有“R”键。不少用户对“R”键的作用了解不多,有的甚至从来都没有使用过。实际上,“R”键是有重要作用的,它是用户使用话机程控新业务(如:追查恶意呼叫、呼叫等待、三方通话等)所必须的按键,包括登记、使用和注销。也就是说,用户需要在话机上的 The telephone set that the user uses, the keyboard usually has “R” key. Many users do not know much about the role of the “R” key, and some never even used it. In fact, the “R” key plays an important role. It is the key that users need to program new services (such as tracing malicious calls, calling waiting, three-way calling, etc.) using the phone, including registering, using and deregistering. In other words, the user needs to be on the phone