A signal switch may also send a query message to the signal control point, which acts as a centralized database for routing instructions, such as how to handle 800/888 calls.

• 信号交换机也可以向信号控制点发送一个查询信息，该信号控制点起到路由指令（如怎样处理800/888对方付费电话）的集中化的数据库的作用。