The multifunctional coupler connects two HDMI cables to create a longer one, eliminating the need to purchase additional, longer cables. Alternatively, the adapter can also be used as a gender changer to convert an HDMI plug into a socket. The passive HDMI coupler either connects two HDMI cables to extend their length or converts an HDMI plug into an HDMI socket. The HDMI-to-HDMI adapter enables high-resolution image transmission of up to 8K at 60 Hz and 4K at 120 Hz, while being backward compatible, with a data rate of up to 48 Gbit/s. It is ideally suited for audio and video transmission between TVs/monitors and projectors, gaming consoles like PlayStation 5, Xbox, or streaming devices such as Amazon Fire TV and Apple TV. The integrated Ethernet Channel (HEC) connects any HDMI device to wired network devices without the need for an additional internet cable. The Consumer Electronics Control (CEC) function allows for flexible operation using just one remote control, for instance, to power on multiple paired HDMI devices with a single button press. It supports 8K UHD as well as 3D at 4K UHD and HDR (High Dynamic Range) for excellent, high-contrast image quality and is compatible with the HDCP 2.2 encryption system. It also supports advanced audio features like eARC (Enhanced Audio Return Channel) and ARC (Audio Return Channel) for easy digital transmission from the TV to a soundbar or hi-fi system.