Most adapters only work in one direction

This is the single most common mistake, and the packaging rarely makes it obvious. A passive DisplayPort to HDMI adapter carries a signal from a DisplayPort source to an HDMI display. Turn it around and it does nothing — HDMI out of a laptop into a DisplayPort monitor needs a different, active converter. The same applies to USB-C and Mini DisplayPort. Check which device is the source before ordering; where a lead is described as bi-directional, that is a deliberate feature worth paying for.

Passive adapters depend on the source supporting the other standard

A passive DisplayPort adapter works because the graphics output can also speak HDMI or DVI — DP++, or dual-mode. Where it cannot, the signal has to be converted electrically and you need an active adapter. USB-C is the same story: a USB-C port carries video only if it supports DisplayPort Alt Mode. Plenty do not, and no adapter can add a capability the port does not have. If a USB-C adapter produces nothing at all on a known-good display, that is usually why.

Going to VGA is a conversion, not an adapter

VGA is analogue and HDMI, DisplayPort and DVI-D are digital, so anything bridging the two contains a converter chip and draws power. There is no passive HDMI-to-VGA plug that works, whatever the shape suggests. VGA is still worth keeping for projectors and older meeting room equipment — just expect a converter rather than a cable.

4K at 30 Hz and 4K at 60 Hz are different products

An adapter rated for 4K may mean 30 Hz, which is visibly unpleasant behind a moving cursor. For desktop use specify 4K 60 Hz and check the whole chain — adapter, cable and display — because the link negotiates down to whichever is weakest.

Brands

VivoLink, Microconnect, StarTech.com and Cables Direct, alongside adapters from Lindy, C2G, Manhattan, DeLOCK, Dell, HP and Lenovo.

Trade pricing and business accounts are available for UK organisations, and bulk orders are welcome — request a quote.