A method for detecting signals in a TMDS transmission system having a channel established between a receiver and a transmitter includes separating loadings of the receiver from the channel, providing a first reference current in a first differential line of the channel, providing a second reference current in a second differential line of the channel, computing a difference between the first reference current and a current provided by the transmitter via the first differential line to obtain a first current difference, computing a difference between the second reference current and a current provided by the transmitter via the second differential line to obtain a second current difference, and determining an operating state of the transmitter according to the first current difference and the second current difference.