Patent ID: 8234433

Claim:
An interface monitoring device for a differential interface port with a positive and a negative data line for connecting a peripheral device, the interface monitoring device comprising: a monitoring circuit coupled with the positive and the negative data line, wherein the monitoring circuit is designed to monitor data traffic on the positive and negative data lines and comprises a comparator for comparing a voltage level of a node with a predetermined reference voltage, wherein the node is connected to a signal input of the comparator, the node being further connected, by a first resistor, to the positive data line and, by a second resistor, to the negative data line, wherein a signal output of the comparator is coupled to a filter circuit for filtering out zero crossings of the voltage level of the node, and wherein the monitoring circuit is further designed to signal a disconnection of the peripheral device from the differential interface port when the voltage level of the node falls below the predetermined reference voltage for a predetermined time period, wherein the filter circuit comprises an RC element with a predetermined time constant that designates the predetermined time period; and a deactivation circuit, wherein the deactivation circuit is designed to stop the data traffic via at least one of the positive and negative data lines of the differential interface port until the interface monitoring device is reset when a disconnection of a peripheral device connected to this port was signaled by the monitoring circuit.