Among the majority of their implementation, media access gateway(AMG) plays a very important role. It transforms the PSTN data frame format into IP packet format, and it also translate the switch signaling and protocols.

• 在VoIP实现方案中，接入媒体网关（AMG）扮演了非常重要的角色，它实现PSTN到IP的数据格式的转换，交换信令和协议的转换，实现系统控制等。