Actually, HDMI is not a digital video format. HDMI is a specification for a type of cable with a particular plug shape that carries signals/data of various types in different formats. Depending on which version the cable is compliant with it will carry audio & video signals, network data and other information. The main focus of HDMI cables is the transmission of digital video and audio to TVs. But they can also carry the legacy analog signals used by VGA monitors without having to convert the signals. For this to work, the device must be able render this type of analog signal. Apparently the Z150 ignores the analog signals. Therefore you would need something that actually actively converts between digital and analog formats, which means some kind of processing chip will be required which will be more costly, and it will require some kind of power source for the chip which will probably be housed in a little box.