自動用戶小交換機;［私用自動交換分機］ A private telephone exchange that automatically connects internal “branch” lines to the external circuits of a telephone system. 一種自動地將內部用戶線連接到電話系統外線的專用電話交換機。 Private Automatic Branch eXchange的縮寫h。
Private Automatic Branch eXchange的縮寫。即自動用戶小交換機，或者私用自動交換分機。 A private telephone exchange that automatically connects internal “branch” lines to the external circuits of a telephone system。一種自動地將內部用戶線連接到電話系統外線的專用電話交換機。