| 摘要 |
A method and a circuit arrangement are disclosed for detecting ring trip in a subscriber line interface circuit (101, 210) coupled to a subscriber line (220) of a wireline telephone network. There is provided an amplifying output stage (102, 213, 214) for feeding a ring signal into the subscriber line (220) and a supply voltage source (104, 215, 216) for providing a supply voltage to the amplifying output stage (102, 213, 214). Additionally there is provided monitoring and detection means (105, 106, 301, 302, 303) for monitoring an electric characteristic internal to the subscriber line interface circuit, said monitoring and detection means (105, 106, 301, 302, 303) being arranged to detect a change in said electric characteristic and to give a ring trip indication on the basis of a detected change in said electric characteristic. |
