Audio, Video and other signals over UTP

CAT 5, 5e and 6 UTP (unshielded twisted pair) cables are the most commonly used communication wiring in building. Those wires are normally designed to carry signals like Ethernet and telephone. Those wires can be also used to carry many other signals. Some signals can be directly wires to them (with suitable adapter cables) and some signals need to adaptation to go nicely over UTP wiring. When properly used UTP wiring will have good performance because the wire is a well balanced twisted construction (for more details read Use a twist (and other popular wires) to reduce EMI/RFI and Video and audio over twisted pair wiring). You need to know how to connect different kind of signal to UTP wiring properly, because wrong kind of connection will make the UTP cable to perform poorly (unbalanced signal directly wired to UTP cable will pick up interference easily). Here are some tips how to do the connection:

RJ45M8P1

Balanced line level audio (XLR or 6.3 mm TRS jack): Balanced audio signal goes nicely over twisted pair. It works normally acceptably without shielding on the wiring. Wiring idea: Wire audio + and – to one wire pair. Use another wire pair to carry signal ground from one end to another (if needed). Use for example RJ-45 pins 1+2 for audio and 7+8 for signal ground.

Unbalanced audio (RCA connectors): Use audio isolation transformers to convert signal to balanced format and back to unbalanced on other end. The output impedance of the signal source (lower the better) and the quality of transformers use affect the signal quality.

Composite video: Video baluns will do to needed signal balancing and impedance matching. There are both active and passive adapters to do this. I have been happy with (cheaper) passive models. Composite video over twisted pair is commonly used in CCTV applications.

S-video: Sepate video baluns for Y and C components works.

RGB: Separate video baluns for each vide component. Make sure that video baluns can handle the bandwidth and have identical performance. There are commercial adapters with three baluns built into one unit.

YUV component video: eparate video baluns for each vide component. Make sure that video baluns can handle the bandwidth and have identical performance. There are commercial adapters with three baluns built into one unit.

VGA: There are commercial active adapters that convert VGA signal to RJ-45 connector

HDMI: There are commercial adapters that convert HDMI signal to UTP wiring. Most converters use two RJ-45 connectors (some more expensive ones can run using one).

S/PDIF digital audio: Use video balun for conversion. The S/PDIF signal is signal levels, bandwidth requirements and impedance is pretty similar to composite video signal, so the baluns designed for video signals work well.

DMX-512 light control network: Works well. The difference between Category 5 and low capacitance 120 ohm EIA-485 cable is too small to be of any noticeable effect in DMX512 transmission and reception. Use RJ-45 pins 1+2 for data and 7+8 for signal ground.

RJ45F8P2

You can find some more detailed information on this topic at Video and audio over twisted pair wiring.

5 Comments

  1. Q-factor says:

    Thank you for this great article!

    Reply
  2. Jems Carrry says:

    Thanks for This UTP model, nice post with great information Thanks for sharing..

    Reply
  3. Helotiaceae says:

    Excellent post. I was checking continuously this blog and I’m impressed!
    Very helpful info specifically the last part :) I care for such
    info a lot. I was looking for this certain info for a very long time.

    Thank you and best of luck.

    Reply
  4. Tomi Engdahl says:

    Passive component extends audio signal reach over Cat 5, 5e, 6 or 6a data cables
    http://www.cablinginstall.com/articles/2016/07/ets-instasnake-audio.html?cmpid=Enl_CIM_CablingNews_July182016&eid=289644432&bid=1466869

    From Energy Transformation Systems, Inc. (ETS), the Single Channel InstaSnake is a passive component that allows a user to send audio signals over Cat5, 5e, 6 or 6a data cables. Designed to operate within those “crunch times” when one needs a quick, handy, reliable audio fix, the Single Channel InstaSnake allows bi-directional mic level, line level, analog or digital audio signals to run over UTP cable up to 1900 ft.

    InstaSnake™ Products
    http://www.etslan.com/products.cgi?cat=9

    The ETS InstaSnake™ Series (PA200) is a compact, lightweight, versatile passive group of components allowing you to run audio signals over a single run of Cat 5, 5e, 6 or 6a data cables. With a roll of cable, these compact units are easily transported and/or stored solving dozens of live and/or recording sound problems.

    The InstaSnake™ is a passive unit, so you do not need power. The InstaSnake™ accepts “mic” level or line level analog or digital audio and supports phantom power when using shielded Cat 5 or 6 cables. The basic units are a pair of passive units with bi-directional capability which can be input directly into analog or digital consoles.

    The ETS CINESNAKE™ Series PA210 is a compact, lightweight, versatile passive group of components allowing you to run audio signals over a single run of CAT5 or better cables.

    The CINESNAKE™ is a passive unit, so you do not need power. The CINESNAKE™ accepts “mic” level, line level, analog or digital audio and supports phantom power when the slide switch is “ON” position.

    One cable carries both audio signals simplifying the user or installer’s job. Ordinary UTP cabling may be used, however distance and quality are enhanced with cat5 or better cable.

    Reply
  5. Tomi Engdahl says:

    4K Images and Pictures: What Do They Really Mean?
    http://www.belden.com/blog/broadcastav/4k-images-and-pictures-what-do-they-really-mean.cfm

    So you want to upgrade to a 4K system? There are several options when it comes to the type of signal your 4K system can send to display 4K images. T

    The Definition of 4K

    Let’s start with the basics: What does “4K” really mean? There are different answers to this question, depending on the industry. The broadcast/video industry defines 4K differently than the motion picture industry. Both industries refer to their versions as 4K images, but they are slightly different.

    The motion picture/film industry has been shooting movies in digital high definition for some time now, moving away from using actual film. If you’ve been to a movie theater recently, chances are good that you watched a 2K Digital Cinema Initiatives (DCI) native resolution image, which has 2048 pixels horizontally and 1080 pixels vertically on the screen. The 4K version of this is 4096×2160 (four times the size of the 2K). On the other hand, the broadcast/video industry’s standard for 4K is four times a 1080p (1920×1080), which is 3840×2160 pixels. The majority of U.S. consumers are working with the broadcast/video industry image, where a 4K image is more precisely referred to as ultra-high definition (UHD).

    Traditionally, frame rates were 24 per second for movies to balance between film costs and creating what seemed to be a “moving picture.”

    Over the years, there has been an increased demand to display more frames per second to better capture action and sporting events. Because of this, you now have the option to double the frame rate to 60 frames per second. A frame rate of 120 is even possible.

    Traditionally, each color is represented by 8 bits of information, which equates to 256 choices per color (2 to the power of 8 choices). With all three colors making up a picture, you have over 16 million choices

    For even more options, the market now offers 10, 12 and 16 bits of information per color.

    Instead of sending three colors, luminance and chrominance red and blue (or YCrCb) are sent. Both color patterns are used for 4K images.

    A traditional TV has a brightness range of about 150 nits. The industry has developed a new TV with a standard called high dynamic range, or HDR, which offers a brightness range of 1,000 nits.

    Bandwidth requirements can be in excess of 18 Gbps. This causes a problem when it exceeds the limits of today’s systems, requiring users to make compromises. You can limit the chrominance information, which is the least perceptible part of the image – as we talked about earlier in the blog.

    You do this by having pixels share chrominance information with adjacent pixels. (If two pixels share chrominance, this is called 4:2:2 sampling; if four pixels share chrominance, it’s called 4:2:0 sampling.) This can help you reduce bandwidth requirements and make it compatible with today’s systems.

    The Future of 4K

    Remember: This is cutting-edge technology, and it’s anyone guess as to where the improvement will stop. In fact, the industry is already working on 8K.

    Reply

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