Patent ID: 8082570

Claim:
An apparatus for reducing noise ingress, said apparatus comprising: at least one interruptible signal path extending from a supplier-side port through a user-side port, each of said interruptible signal paths comprising a conductor and a prescribed signal level connection point; a signal source coupled to at least one of said interruptible signal paths, said signal source arranged to provide a signal to said conductor; and at least one signal circuit, each signal circuit being arranged in one of said interruptible signal paths, each signal circuit configured to determine, based on a value of said signal, when said interruptible signal path is unterminated, and to interrupt and terminate said interruptible signal path to said prescribed signal level connection point when said interruptible signal path is determined by said signal circuit to be unterminated, wherein each of said signal circuits determines whether at least one of said interruptible signal paths is unterminated by determining an impedance on said conductor, and comparing said impedance to a reference value.