Published on 29th Oct, 2013 by Cable Chick

What you need to know about Active vs Passive cables, switches & splitters

What you need to know about Active vs Passive cables, switches & splitters

What you need to know about Active vs Passive cables, switches & splitters

We hear the terms 'active' and 'passive' attributed to cables and equipment all the time. But what does it mean? Which one is better? Which one do you really need? We clarify the difference and explain how to choose between them.

What's the difference between passive and active products?

In terms of the products we stock here at Cable Chick, we consider any product that requires extra power to operate (eg: from a wall socket or extra USB cable) to be ‘active’, and products which operate on their own as ‘passive’. Other vendors or manufacturers may make a different distinction, but for simplicity, if it needs a power cable plugged into it, then it’s usually active.

One grey area in this definition are cables which use power from the source device to run internal electronic chipsets or circuit boards. These products typically use HDMI or USB, as those sockets have the most versatile 5v rail built-in.

Another special case is DisplayPort, which is detailed below

What benefits are there when using Passive cables and adapters?

Passive Cables, Adapters and Switches have a huge advantage when working with content-protected source devices (ie: HDCP, Macrovision). Because there is only copper wire between the source and display, your signal is never processed by hardware or software which may adjust or strip important data from the stream.

We find that when working with sources like Apple TV, Foxtel, Austar and similar Pay-TV services, our customers have greater success and better results when working with passive products.

And because Passive products don’t require any extra power, there is no standby usage or requirement for a mains wall socket. They’re simply plug and play, and your AV hardware won’t even know they’re there.

What are the benefits of using Active adapters and converters?

Active products have a huge advantage when working with long cable runs and video conversion applications. Because they take power from an external source, they have the grunt to boost your AV signals over longer distances. This can be important when working with mobile devices running on battery power, as they may not have the output strength to support, for example, a 20m HDMI cable on their own.

In terms of video converters, active units generally have upscaling hardware inside to improve your image. If your source device is standard-definition analogue and your display is Full HD or 4K, the extra processing grunt can make the image quality more bearable.

Finally, Active products are generally more powerful, which gives us splitters and matrixes which can power 2, 4, 8 and more screens at once while maintaining maximum audiovisual fidelity (passive devices are generally limited to a single screen).

What about the grey area?

We do our best to label only truly passive products as passive, but we do have a couple of products which need no external power and still have built-in chipsets. With these products, you’re usually making a compromise between the two camps.

The advantage is that these semi-active products can do more than their passive counterparts without needing that 240v power supply, but generally fall short of the performance an active product can achieve.

For example, our Passive HDMI to VGA + 3.5mm Stereo Audio Adapter isn’t great for 1080p Full HD conversions, but if an external power source is a bigger problem than maximum resolution, it makes a great middle ground.

Other semi-active products include:

Should I choose an Active or Passive product?

This can be a tough decision, and many customers have lost their sanity trying to find an active version of a passive product and vice-versa. The first step in choosing is to investigate what your requirements are in terms of content/copy protection, video resolution, cable length, and power availability. Then, compare those needs to the specifications on the products we stock.

Bandwith loss over long cables (particularly with DVI and HDMI) can result in lowered resolution capaibilities, too. For example, expecting a very cheap 20 metre HDMI cable to manage a 4K resolution is somewhat unrealistic (even though it's a High Speed cable). But at the same time, booster chipsets currently only support 1080p anyway. In this example, you'll want to look at better quality passive cables over the entry level range, or find a way to shorten the distance.

Our advice is to always start with the shortest passive length you can, and if it doesn't meet your requirements start looking at the trade-offs on the other solutions. Don't forget to check our blog on Maximum Cable Lengths for more info on what the limitations are for both active and passive solutions.

We’re here to help, too! Feel free to contact us if you’d like extra advice. Simply let us know your source and destination device(s) and we’ll let you know your options.

I was told I need an active DisplayPort adapter. Do I really?

DisplayPort is a special case in terms of Active vs Passive, and it really comes down to the question of whether or not you’re using an ATI/AMD Eyefinity multi-monitor graphics card with 3 or more non-DisplayPort screens and/or your display(s) have a native resolution higher than 1920x1080@60.

For most basic connections to a single Full HD monitor, a basic passive DisplayPort cable or adapter will be sufficient to get your screen working. This assumes your source device is DP++ compatible - most are these days, but it won’t hurt to check.

The reason high-end Eyefinity-ready gaming PCs using 3+ monitors require an active DisplayPort-to-HDMI or -DVI adapter is because most Eyefinity video cards only have 2 TMDS clocks, and they’re already in use by the GPU's actual HDMI and DVI sockets. By plugging in a passive adapter, it’s one TMDS short (because of how DisplayPort sockets pass through HDMI/DVI data to the adapter).

Cable Chick does not currently stock an Eyefinity-compatible active DisplayPort adapter, or a DisplayPort adapter with the grunt to convert to dual-channel DVI for higher-than-HD screens. If you need such a product, please ask at your favourite computer parts specialist, or at the store which sold you the PC or Video Card.

Another potential issue with DisplayPort on computers is an ongoing bug with DisplayPort screens not activating during boot time, but we won't go into that here. All of Cable Chick's DisplayPort cables and adapters are certified VESA compliant by an independent third party.