A.Setup B.Call-proceeding C.Alerting D.Progress
A.Progress B.Call-proceeding C.Alerting D.COnnecting
A.網(wǎng)守接受了該網(wǎng)關(guān)的注冊 B.網(wǎng)守拒絕了該網(wǎng)關(guān)的注冊 C.網(wǎng)關(guān)傳送的參數(shù)錯(cuò)誤 D.網(wǎng)守正在處理網(wǎng)關(guān)的注冊請求