PROMATE PROLINK4K60-20M Unidirectional HDMI® Cable / 4K@60Hz Resolution / 18Gbps Transfer Rate / 20m Optical Fiber Cable / Gold-Plated Connectors / Ethernet Support for Internet Sharing / PROLINK4K60-20M / PROLINK4K60-20M

The Promate PROLINK4K60-20M is a 20-metre unidirectional optical fibre HDMI cable carrying 4K at 60Hz with an 18Gbps transfer rate. It uses gold-plated connectors and supports the HDMI Ethernet channel. Optical fibre is what makes a run this long viable without the signal degrading along the way.

The cable carries 4K at 60Hz rather than the 30Hz that cheaper long HDMI runs fall back to. The difference is immediately visible on motion: 30Hz makes panning shots and mouse movement look stepped, while 60Hz keeps them smooth. For a projector or a display used as a monitor, that refresh rate is the deciding specification.

Transfer rate is 18Gbps, which is the bandwidth 4K at 60Hz requires with full colour information intact. Bandwidth is where long copper cables fail first: they carry a picture but drop colour depth or chroma sampling to do it, producing washed-out text and colour fringing that people wrongly blame on the display.

The cable spans 20 metres in a single length. Because the signal travels as light through optical fibre rather than as electricity through copper, distance does not attenuate it the same way, so the run needs no inline repeater, booster or extender box. That means one cable and no additional powered hardware in the ceiling.

This is a unidirectional cable, so one end is intended for the source device and the other for the display. Optical HDMI converts the electrical signal to light at one end and back at the other, which means the cable only works when connected the right way round. Confirm the orientation before routing it through a wall.

Both connectors are gold plated. Gold does not oxidise, so the contact surface stays conductive over years in a humid room or behind a wall plate, where bare metal contacts slowly build a resistive film. On a cable installed permanently in a ceiling or conduit, that longevity matters far more than it does on a desk lead.

The cable supports the HDMI Ethernet channel, which lets two connected devices share a network link over the same cable that carries the video. Where the display end of a long run has no convenient network point, that removes the need to pull a separate data cable alongside the HDMI one.

A 20-metre run suits the installations where the source and the screen are nowhere near each other: a ceiling-mounted projector in a home theatre, a conference room display driven from a rack, or a console sitting on the far side of a lounge. In each case the length is what removes the compromise.