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Passive vs. Active, that is the question

Posted by Frank Farnsworth on Fri, Aug, 19, 2016 @ 09:08 AM

We’ve all been there, scratching our heads, slowly losing our sanity saying, “What’s the difference between passive and active adapters and what is that double plus sign above the port anyways?” DisplayPort is being seen more and more in the world of hardware for digital signage and video walls, and for good reason!



DisplayPort Benefits

  • The standard surpasses HDMI 1.4 in capabilities (HDMI 2.0 has not been widely adopted yet)
  • You can fit more outputs in a given space over other video standards (mini DisplayPort is half the size of HDMI)
  • Manufacturers don’t have to pay royalties when implementing it into their product 

With those benefits comes a particular headache that anyone deploying a visual media solution has probably had to deal with at least once—do I need passive or active adapters!?

The first step in choosing passive or active is knowing the type of installation and what is needed. What graphics hardware am I using? How many monitors will be used, and what input am I looking to utilize on them? What is the video resolution? Will the content display on one monitor or span across several monitors? Knowing the answers to these questions will help in the decision making process.

When To Use Passive

The biggest question asked when a DisplayPort media player is purchased is “why do I need to pay so much for active adapters when the passive ones come in at half the cost (or less)?” Passive adapters are less expensive since they do not have a built-in converter or DAC Chip. They rely on the system’s DisplayPort to detect the monitor and output the required signal. Passive adapters can be used when a system has a dual-mode DisplayPort—marked with DP++ symbol over it since this port carries the HDMI or single-link DVI signal natively.

When To Use Active

An active adapter uses an internal chip separate from the video source (computer or digital media player) that does the conversion to the desired type of output; whether that be HDMI or DVI. These are required for high-output video cards and tend to alleviate a world of problems for customers who choose to source their own adapters. There are even active adapters for particular resolutions, so if you’re running 4K over HDMI, make sure your chosen adapter supports it!

Active adapters are ideal for graphics card that do not output dual-mode signals and can support a video that displays across multiple monitors. Active adapters aim to create an assisted bandwidth perception that will enable a more streamlined result across a full array of monitors. They essentially make the video output believe it’s connected via DisplayPort, while converting to the required signal type to the screen, allowing the array of outputs to function as designed. A 6-output mini DisplayPort card, for example, desires to be connected to six DisplayPort monitors, and the only way to make the card think it’s doing that is with active adapters.

What is DP++?

Natively, dual-mode DisplayPort (DP++) supports multiple displays and takes care of HDMI/DVI signal conversion before it leaves the box—the conversion is built-in to the video card or motherboard. You can tell if your system has this feature by looking for the “DP++” icon above or below the port (see the image below). However, DP++ has its limitations; you will be hard pressed to find it on more than 2 outputs, and is really only found to be supported by Intel® or AMD® integrated graphics currently.

seneca HDN


Final Decision

In the end knowing the specification of your setup will help you in making the final decision of using passive or active adapters. There are situations where either solution can help you best accomplish your goals! Still need help in the decision making process? Consult with a Seneca product development specialist and they will work with you to make your installation a success.


Topics: media player, digital signage, active adapter, passive adapter

Posted by

Frank Farnsworth

Frank is the Lead Development Engineer in Seneca’s Visual Media market. He is responsible for designing custom solutions and validating platforms for customers looking to deploy products in Digital Signage and Digital Broadcast.

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