| 摘要 |
An electric device ( 202, 301 ) for connecting an analogue data transfer device ( 202 ) by means of a control unit ( 203 ) to a digital transfer system comprises means for connecting to a data transfer device via a twin cable ( 204 ). In addition, it comprises a current amplifier arrangement ( 214, 314, 340 ) for feeding a certain current to the twin cable, a first current switching device ( 219 ) for switching a first control current to the current amplifier arrangement, and a second current switching device ( 220 ) for switching a second control current to the current amplifier arrangement. The current switching devices ( 219, 220 ) are preferably current mirrors. |
