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Video Extenders Explained
What is a Video Extender?
Standard video cables have a maximum length beyond which the signal degrades, which is a problem when the video source and display are not in close proximity. A video extender allows a video signal to be transmitted over a much longer distance with no loss of signal quality.
What is a balun?
Balun (a combination of the words "balanced" and "unbalanced") is a somewhat outdated term for a device that converts the signal on a balanced line (like a twisted pair) so it can be transmitted over an unbalanced line (like a coaxial cable) and vice versa. In common usage, balun has been largely replaced by the term "extender."
How do Video Extenders Work?
Video Extenders convert a video signal into a form that can be transmitted over a greater distance. Audio and control signals can be sent alongside the video.
Some extender kits are adapters as well. For example, Tripp Lite's B127A-1A1-BDBH extends a 4K DisplayPort signal over Cat6 up to 230 feet to a receiver that converts it to HDMI for display.
Types of Video Extenders
Active cables have a built-in booster (also known as a repeater) that regenerates and forwards the signal. This circuitry may be in the connector on the receiving end or in the middle of the cable.
Active cables typically work in one direction only: from a video source to a display. The connectors on each end of the cable indicate which is the sender and which is the receiver. Do not use active cables in conjunction with any other form of extender.
Before pulling cables through ceilings or walls, connect all components and make sure an image is displayed and the quality is acceptable.
Active Optical Cables (AOCs)
Originally intended as a high performance alternative to copper patch cables in data centers, Active Optical Cable (AOC) can transmit data or video over long distances.
The connectors on a video AOC include a transceiver that converts electrical signals to light pulses so data can be transmitted over fiber optic cable. When the light pulses reach the other end of the cable, they are converted back to their original format.
In addition to higher transmission speed, AOCs are not susceptible to signal distortion due to electromagnetic interference (EMI) and are thinner, making them easier to install.
CATx Video Extenders
These extenders transmit video signals over relatively inexpensive Cat5e or Cat6 cable and can reach distances of 295 ft. (90 m). CATx cable is also easy to install and field-terminate.
Most extenders that send video over a CATx cable use proprietary signal conversion and the result is not a standard stream of Ethernet packets. This means that the CATx cable must directly connect the transmitter that encodes the signal and the receiver that decodes it. A compatible repeater can be used for greater distance. If you want to use an Ethernet network switch to distribute video, you'll need an AV over IP extender (see below) that does use standard Ethernet protocol.
AV Over IP Extenders
Similar to CATx video extenders, these IP-based extenders use standard TCP/IP to distribute video, audio and control signals. The use of TCP/IP means video can be distributed over an existing local area network, making installation easier and less expensive. It can also make use of standard network components like switches to connect video sources and displays.
HDBaseT Video Extenders
The HDBaseT standard provides a simple way to distribute audio, video and data up to 100 meters (328 feet). A key concept of HDBaseT is 5Play, the transmission of uncompressed digital video and audio, Ethernet, USB, control signals and power over a single category cable (Cat6 or above). The primary benefit of HDBaseT over other alternatives, such as CATx or AV over IP, is device compatibility. As an industry standard, an HDBaseT device will work with any other HDBaseT-compatible device, regardless of the manufacturer.
Fiber Video Extenders
Extending a video signal over fiber results in low signal latency and the longest transmission distance available, up to 1,000 feet (300 meters) using multimode fiber and 6.2 miles (10 kilometers) with singlemode. Similar to the Active Optical Cables described above, fiber extenders are not affected by electromagnetic interference (EMI) and crosstalk.
Wireless Video Extenders
When it is difficult to run cable or when the placement of the video source or display changes frequently, a wireless video extender may be the answer. Wireless extenders send 1080p and 4K video and 7.1 channel audio signals up to 165 feet (50 meters).
For best results, manufacturers may recommend that the transmitter and receiver are in line of sight. Transmission through walls, glass or brickwork is possible but it can reduce signal range. In a typical setting like a conference room, signal range is generally not a problem because the distance between source and display is short.
Extender Methods and Capabilities
Note: Maximum distance and resolution have an inverse relationship. Longer transmission distances typically mean a lower resolution, reduced color depth or color compression (chroma subsampling). Refer to product specifications for more information.
|HDMI Cable||150 ft.
|4K/60||DTS-HD, Dolby TrueHD, 7.1-ch||IR, USB
|AC, PoC||See Products|
|4K/30||DTS-HD, Dolby TrueHD, 7.1-ch||IR
|AC, PoC||See Products|
|4K/30||DTS-HD, Dolby TrueHD, 7.1-ch LPCM||IR||AC||See Products|
|DP Cable||150 ft.
|1080p||8-ch LPCM||No||Bus||See Products|
|4K/60||DTS-HD, Dolby TrueHD, 7.1-ch||IR, USB
|AC, PoC||See Products|
|DVI Cable||100 ft.
|1080p||No||IR, Serial||AC||See Products|
|CATx||1,000 ft.||1080p||Yes*||IR, Serial||AC||See Products|
Component Video Extenders
|1080i||Stereo||IR, Serial||AC||See Products|
|wireless||185 ft.||4K/30||7.1-ch LPCM
Extender Signal Distance
All video extenders have a maximum range, regardless of how they extend the video signal. This limitation may be inherent in the signaling protocol or the result of attenuation. In some cases, the maximum range can be increased through the use of a signal booster.
|Extender Type||Product Examples||Typical Distance||With Repeater(s)|
|Active Cable||P568-100-ACT||100 ft.|
|CATx||B127A-1A1-BHPH||230 ft.||920 ft.|
|Active Optical Cable||P568-100M-FBR||330 ft.|
|AV Over IP||B160-101-DPHDSI||330 ft.|
|HDBaseT||B013-HU-4K||330 ft. (1080p)
230 ft. (4K UHD)
|AV over Fiber||B127F-1A1-MM-HH||1,000 ft. (MMF)
6.2 mi (SMF)
Using a Signal Repeater for Greater Distance
A signal repeater (also known as a signal booster or signal amplifier) lets you increase the strength of a video signal so it can travel greater distances. A repeater receives a signal from a transmitter, regenerates it and transmits the new, strong signal to a receiver or another repeater.
Transceivers, a combination of a transmitter and receiver, can be connected serially to create daisy chains. This is ideal for digital signage installations in which all displays show the same image. Up to 4 transceivers can be used to create a chain over 920 feet in length.
Extender Mounting Options
These so-called "box style" extenders can be placed on a tabletop or shelf. They typically come with mounting brackets for wall mounting.
Box style extenders can also mounted in a rack enclosure or attached to a pole or display mount.
As the name suggests, these extenders can be screwed to a surface mounted outlet box for a clean, professional look. They are ideal for offices, classrooms and other public places.
Pigtail extenders attach directly to the video source or display using a short built-in cable.
Choosing the Right Cable for a CATx Video Extender
CATx video extenders use category cable to transmit video, audio and control signals. Category cables are classified according to their performance characteristics, with designations of Cat5e, Cat6, Cat6a, Cat7 and Cat8 indicating their bandwidth, speed and maximum length. Cable specifications are dictated by the TIA standards but, depending on the gauge of the conductors, shielding and quality of construction, a category cable's actual speed and maximum distance may exceed the specification.
All CATx cables are backward compatible to Cat5e and use the same RJ45 connector, so you can choose any CATx cable for your CATx video extender. However, to ensure that the cable will reliably carry even higher resolution video in the future, particularly if the cable will be difficult to replace, you should at a minimum use solid core Cat6 or Cat6a cable.
To ensure the best picture quality, follow these general guidelines:
- Use Cat6, Cat6a or better cable
- Choose pre-terminated, solid core cable (all Tripp Lite N202-Series Cat6 cables are made with 24 AWG solid copper conductors)
- Use shielded cable to avoid signal distortion from AC power lines, fluorescent lights and RF radios
- Keep cable lengths to the minimum necessary, especially with higher resolution video. For example, if you need to span
You can find more information on category cables in our Ethernet Cable Technology Primer.
Plenum or Riser Rated Cable
Plenum is the space above or below a room that provides a way for air to return to a building's HVAC system. A riser is a vertical shaft between floors for electrical wiring, water pipes, and voice or data cabling. In the event of a fire, it's critical that cabling in these areas does not promote the spread of smoke and toxic fumes.
When selecting cable to run through plenum or risers, look for CATx cable with a jacket rating of CMP (plenum) or CMR (riser). These cables have a higher degree of fire resistance and emit fewer toxic fumes compared to general purpose CM or CMG rated cables. In the US, the NFPA's National Electrical Code (NEC) guidelines requires CMP or CMR cabling for plenum or risers and compliance may be a contractual or legal requirement. Because CMP cables have a higher fire resistance, you can use CMP in risers but you cannot use CMR cable in plenum spaces.
If you need to run cable outside (for example, if the cable will be buried or exposed to moisture or sunlight), use a cable with a CMX-rated jacket. CMX cable is waterproof and resists drying and cracking due to long-term sun exposure. It can also be buried without a conduit.
In situations where extender cables will be subject to frequent connection and disconnection, consider cables with an antibacterial jacket. Tripp Lite's Safe-IT video, USB and Ethernet cables are made from an antibacterial material that is 99.9% effective in inhibiting Escherichia coli (E. coli) and Staphylococcus aureus (staph).
Extender Features to Consider
Aside from the video interface, distance and resolution, there are other extender features that may be important in certain circumstances. Here are a few to consider:
High-Bandwidth Digital Content Protection (HDCP)
This authentication protocol allows a sending and receiving device to verify each other's credentials (stored on each device's Extended Display Identification Data (EDID) chip) and, if every checks out, create a shared key that is used to encode and decode the data passing between them. This process, known as a handshake, happens almost instantaneously at the beginning of a session and ensures that an unauthorized device cannot intercept the data as it travels between two devices.
In the United States, HDCP support is mandated by the Federal Communications Commission (FCC). Providers of high-resolution digital video and audio use this anti-piracy copy protection to prevent unauthorized use and copying of their content and will give an error, or transmit at a lower resolution, if HDCP is not supported. For example, Amazon or Netflix will transmit 1080p instead of 4K if they cannot establish an HDCP-compliant connection to the display.
High Dynamic Range (HDR)
HDR is achieved by sending additional information with the video signal that tells the TV or monitor how to display the content. It results in greater brightness, contrast, and better color accuracy as compared to Standard Dynamic Range (SDR). Dynamic HDR simply means the dynamic range can be set on a per-scene basis (or frame-by-frame in the case of high-end TVs).
A color space is a defined range of colors that can be represented in a video image. The two primary color spaces used to represent digital video are RGB and YCbCr. Two important characteristics of a color space are Color Depth and Gamut.
- Color Depth is the number of bits used to represent the color of a single pixel and determines the amount of shading or gradation.
- Gamut refers to the number of colors available.
It is worth keeping in mind that the human eye can only distinguish around 10 million different colors, so 24-bit color is adequate for most situations.
|Color Depth||Bits per Color||Also Known As||Gamut|
|24-Bit Color||8||True Color||16.7 million|
|30-Bit Color||10||Deep Color||1.073 billion|
|36-Bit Color||12||68.71 colors|
|48-Bit Color||16||281.5 trillion|
Chroma subsampling is a form of video data compression. It reduces the amount of color data in a video signal in such a way that there is little or no visible impact on image quality.
Each pixel in a video image includes information on brightness (luma) and color (chroma). Since human eyes are more sensitive to differences in brightness than color, chroma subsampling reduces the amount of data transmitted by allowing pixels to share color data with adjacent pixels.
Chroma Subsampling is represented as three digits. The first number is the number of pixels in each row of the sample. The second number indicates the number of pixels in the TOP row that have color information. The third number indicates the number of pixels in the BOTTOM row that have color information.
- 4:4:4 means no subsampling. Each pixel has its own color information.
- 4:2:2 indicates that two adjacent pixels on each row share color information, representing a 50% reduction in color data.
- 4:2:0 means the bottom row has no color information and uses the information provided for the top row. This approach reduces the color data by 75%.
How to Extend Audio
HDMI, DisplayPort and USB-C extenders transmit audio alongside video to remote receivers. Once the audio reaches the receiver, it can be output through a television, speakers or AV receiver. Audio can also be extracted (separated) from the video signal and output through a receiver's Toslink optical audio port to a home theater system, sound bar or amplifier.
The DVI and VGA interfaces do not support audio but an extender may provide audio support, for example through a 3.5mm stereo port.
Powering Transmitters and Receivers
Extending a video signal requires power. Sometimes, the power can be supplied by the sending or receiving device through a USB port (also known as bus power) or the video port itself (e.g. HDMI). Other situations may require an AC power adapter or some other power source.
Local AC Power
An AC adapter may be used to power a transmitter, receiver or both. This is usually not a problem since video sources and remote displays require local power anyway. When local power is "dirty" (e.g. voltage spikes or line noise), consider adding a surge protector. If it is critical that a video distribution system stay up and running during a blackout or similar, add UPS battery backup. This will keep essential components powered during a power event and can regulate voltage too.
USB "Bus Power"
All USB ports supply "default" power levels. USB 2.0 ports deliver 5V at 500 mA, for a total power output of 2.5 watts. USB 3.0 and 3.1 allow 5V at 900 mA (4.5W). Higher power levels are also supported through standards such as USB-C Power Delivery.
Power over Cable
Power over Cable (PoC) technology allows a transmitter connected to an AC outlet to power a remote receiver over Cat6 cable. PoC lets you avoid installing a bulky AC adapter beside the receiver, and gives you the freedom to place the receiver away from an AC outlet.
Are Power over Cable (PoC) and Power over Ethernet (PoE) the same thing?
PoC and PoE are similar technologies. They both allow data and power to be transmitted from one device to another over a single CATx cable. The difference is that PoE is based on a set of standard specifications whereas PoC is proprietary and designed to meet the power needs of a specific device.
You can learn more about Power over Ethernet in our technology primer.
How to Use IR, USB and RS-232 Remote Control
Controlling a Remote Display or Video Source with IR
If a remote display supports infrared (IR) remote control (e.g. a TV with a remote control) but you do not have line-of-sight from the video source to the display, the distance to the remote display is too great, or there is interference or obstruction in between, you will need an extender that supports IR. Control signals received by the transmitter through an attached IR sensor are sent over the extender cable and relayed to an "IR Blaster" connected to the remote receiver. An IR Blaster is placed in front of the TV and emulates a remote control, forwarding control signals to the TV as infrared.
Some extenders support bi-directional infrared (IR) signaling, enabling you to control your video source from the remote location. This is especially useful when the IR is blocked because the video source is in a closet or behind glass.
Transmitting Mouse and Keyboard Actions with USB
Some extenders have USB ports on the receiver so a keyboard and mouse can be connected along with the remote display. This enables the video source to be controlled as if all components were on the same desktop.
To complete the USB connection, the transmitter is connected to an available USB port on the source device.
How to Use a Local Display
Imagine a set-up in which a computer is using an extender to transmit a video signal to a display 300 feet away in a different part of the building. Wouldn't it be good to know what is being displayed on the remote screen without having to go and see for yourself? Some transmitters include a local "loop out" video port for just this purpose. Connect a monitor to it and it displays the same image as a remote display. This is particularly useful when using IR or RS-232 for remote control.
A video switch accepts multiple inputs and outputs to one TV, projector or computer monitor. The choice of which input to display can be made manually using push buttons on the switch itself or remotely via IR or Serial (RS-232) commands.
Switches avoid the need to manually disconnect and reconnect sources. A simple case would be a conference room in which a presentation included a Powerpoint presentation on a laptop and a video from a Blu-ray player.
A matrix switch has multiple inputs and multiple outputs.
A video splitter takes a single video input and replicates it to multiple displays. An example might be a restaurant menu where each display shows the same image. The splitter is typically placed near the video source and connected to each display using a passive video cable or Cat5e/Cat6 cable.
Any time a video signal is split there is a potential impact on the picture quality.
What is the Transition Minimized Differential Signaling Used to Transmit Video?
Digital signals are a series on "ones" and "zeros" represented by a change in voltage. One is represented by 5V DC and zero is 0V DC. When digital signals are transmitted over copper wires, they are susceptible to noise, interference and signal loss.
Transition Minimized Differential Signaling (TMDS) was developed to reduce the likelihood of video signal distortion. It is used by the DVI and HDMI video interfaces.
- Differential Signaling means the same signal is sent over different conductors, with one being the mirror image of the other. When both signals reach their destination, the mirrored signal is inverted and the two signals are compared. Any difference between the two is assumed to be noise and discarded.
- Transition Minimized means the data is encoded in such a way that the number of transitions between one and zero are minimized, thereby reducing the possibility that the signal becomes corrupted.
What is Video Equalization (EQ)?
When high-resolution video is split or transmitted over a long distance, the picture quality may degrade, becoming dim with smearing or sparkles. Some extenders include a built-in equalizer that will compensate for loss of picture quality by conditioning and amplifying the signal.
What is Auto EDID?
Extended Display Identification Data (EDID) is information embedded in a display's circuitry describing its capabilities, including its screen size and maximum resolution. When the display is connected to video source, it sends its EDID so the source can automatically adjust the video signal to provide the best match.