VGA and USB, the interfaces on this site's monitors
VGA carries analogue video from a computer to a display, and it has served displays for decades, which makes it widely compatible, though it does not carry touch or audio, and its analogue signal can lose quality over long cables. USB carries touch data from a touch display back to the computer, so the computer knows where the screen was touched, and it also powers some small displays. A touch monitor that uses VGA plus USB therefore needs two cables: one for video, one for touch, and both must be connected for the monitor to work fully.
That two-cable arrangement is normal for the monitors on this site, and a buyer who connects only the VGA cable will see a picture but will not have touch, while a buyer who connects only the USB cable will have touch data with no picture. Both cables must be connected, and the inquiry should confirm the cable set for the exact model, because cable sets differ by model.
HDMI as an OEM option
HDMI carries digital video, and often audio, over a single cable, and it is offered as an OEM option on the monitors on this site, rather than as the standard interface. A buyer who needs HDMI should name it explicitly in the inquiry, because the standard interface is VGA plus USB, and an HDMI model is a different configuration, not the same model with a different cable. HDMI's digital signal suits a sharper display, and it carries audio where the display has speakers, but it does not by itself carry touch: a touch display over HDMI still needs a USB connection for touch data, unless its touch runs over another channel.
A buyer who chooses HDMI should confirm the full interface set for the exact model: video over HDMI, touch over USB, and any audio arrangement, because assuming HDMI covers everything will leave touch unconnected. The specification table on each monitor page states the interfaces for that model, and the inquiry should confirm them.
Choosing an interface
Choose by the computer and the installation: VGA plus USB where the computer has VGA output and USB ports, HDMI where the computer has HDMI output and a sharper display is needed, and always confirm the touch channel, because video alone does not give touch. Check the cable lengths as well: analogue VGA loses quality over long cables, while digital HDMI holds its quality further, but both need cables that reach, and a cable that is too short cannot be stretched.
A buyer who is unsure which interface their computer has should check the computer's outputs before ordering the monitor, because a monitor with the wrong interface cannot be connected without an adapter, and an adapter adds cost and a point of failure. The inquiry should name the computer's outputs, so the supplier can confirm the interface set.
Before payment, confirm the minimum order quantity, lead time, payment, shipping and warranty terms for your order. Certificates are available upon request.
Future-proofing an interface choice
An interface choice should consider the future as well as the present: a computer that has VGA today may be replaced by one with only HDMI tomorrow, and a display ordered with only VGA will then need an adapter, while a display ordered with HDMI as an option will already suit the new computer. A buyer who expects to replace computers should consider ordering displays with the interface the next computers will use, or with both interfaces where available, so the displays survive the computer replacement rather than needing replacement with it.
Future-proofing does not mean ordering every interface available: it means ordering the interfaces the installation will plausibly need over the display's life, and no more, because interfaces that are never used add cost without benefit. A buyer who plans computer replacements should say so in the inquiry, so the supplier can confirm which interface set suits both the current computers and their replacements.