地區維護站 設施及設備維護站 訊框 人機介面語言 中介設備 光終端機 非同步數位階層 調度及管理系統 傳輸次網路維運控制系統 Area maintenance station AMS Facility and equipment maintenance station FEMS Frame relay FR Man machine language MML Mediation device MD Optical line terminating equipment OLTE Plesiochronous digital hierarchy PDH Provisioning and management system PAMS Transmission subnetwork controller system TSNC