| 摘要 |
The circuit includes several transistor switches for controlling routing of supply voltage (T1,T7), for a current sensor switch (T2,T6), and a current sensor (T4,T5) for each subscriber line (a,b). The transistor switches are operated by a control mechanism (MC) which reduces the no-load current of unused subscriber lines. A number of subscriber lines are switchable over further outputs (A2-CN) of the control mechanism. Resistances (R1,R2) of the transistor switch for the supply voltage preferably form a sensor current source for the subscriber lines together with further transistors (T1,T3). |
