Uma opção com HDMI é se tanto um monitor quanto uma placa gráfica suportam HDMI-CEC . Dito isso, não acredito que muitas placas gráficas tenham esse suporte.
Não sei por que exatamente, possivelmente devido a motivos de licenciamento e mais uma coisa para oferecer suporte, mas essa tecnologia permite controlar várias funções em uma TV / monitor:
- One Touch Play allows devices to switch the TV to use it as the active source when playback starts
- System Standby enables users to switch multiple devices to standby mode with the press of one button (except LG TV's)
- Preset Transfer transfers the tuner channel setup to another TV set
- One Touch Record allows users to record whatever is currently being shown on the HDTV screen on a selected recording device
- Timer Programming allows users to use the electronic program guides (EPGs) that are built into many HDTVs and set-top-boxes to program the timer in recording devices like PVRs and DVRs
- System Information checks all components for bus addresses and configuration
- Deck Control allows a component to interrogate and control the operation (play, pause, rewind etc.), of a playback component (Blu-ray or HD DVD player or a Camcorder, etc.)
- Tuner Control allows a component to control the tuner of another component
- OSD Display uses the on-screen display (OSD) of the TV set to display text
- Device Menu Control allows a component to control the menu system of another component by passing through the user interface (UI) commands
- Routing Control controls the switching of signal sources
- Remote Control Pass Through allows remote control commands to be passed through to other devices within the system
- Device OSD Name Transfer transfers the preferred device names to the TV set
- System Audio Control allows the volume of an AV receiver, integrated amplifier or preamplifier to be controlled using any remote control from a suitably equipped device(s) in the system
Suspeito que você poderia obter um dispositivo USB que poderia adicionar esse sinal, talvez pesquise USB to HDMI CEC
se quiser investigar essa opção.