| 摘要 |
The aim of the invention is to describe a network termination unit for generation of a call voltage, by means of which it my be guaranteed that a pre-determined maximum power consumption in the confines of a telecommunication network is not exceeded, particularly in the case where the network termination unit draws electrical power exclusively from the telecommunication network. Said aim is achieved, whereby a maximum permitted value for the power which the call generator may draw from the telecommunication network may be pre-set and that means are provided which are intended to keep consumption below said maximum permissible value on a call to the user terminal. It is thus possible, for example, that a high-impedance loop is given a relatively high call voltage supply and correspondingly a low-impedance loop is given a relatively low call voltage supply. Said adjustment of the call voltage corresponds to the creation of a loss-free virtual inner resistance for the call generator. The effect of this device can be seen for example in a change in call current IR which occurs within very precise limits. The product of call generator supply voltage and call current IR which characterises the power consumption is thus essentially constant and maintained below a maximum permissible value for power consumption. |
