Patent ID: 7406607
Filing Date: 2008-07-29
Classification: G09G

Abstract:
1. A controller for a host device and a monitoring device connected on the basis of DVI standard comprising: a host device and a monitoring device connected with each other on the basis of DVI standard for digitally transmitting a video signal through at least one optical extension cable based on DVI standard; a (DDC+5V) signal source that is provided in the host device and generates a (DDC+5V) signal; at least one external power source that drives attached circuits of the host device and the monitoring device; a first detector part that detects whether a (DDC+5V) signal transmitted from the host device is the proper signal or not, and the external power source has been turned on or not; a (DDC+5V) signal transmitting part that transmits a (DDC+5V) signal to the monitoring device only when the proper (DDC+5V) signal is detected in the first detector part as well as the fact that the external power source has been turned on is detected; a HPD signal source that is provided in the monitoring device and generates a HPD signal as a return signal for the (DDC+5V) signal transmitted to the monitoring device from the (DDC+5V) signal transmitting part; a second detector part that detects whether a HPD signal generated from the HPD signal source is the proper signal or not; a power supplying part that supplies the power of the external power source to the attached circuits of the host device and the monitoring device in response to a control signal outputted from the second detector part when the HPD signal is the proper signal; a third detector part that detects the power supply operation of the power supplying part; and a HPD signal transmitting part that transmits the HPD signal to the host device in response to a control signal outputted from the third detector part when the power supply operation of the power supplying part is detected by the third detector part.