Comparing HD CCTV Technologies

March 29, 2018 at 8:00 AM


There are four primary HD-over-coax technologies: Analog High Definition (AHD), High Definition Composite Video Interface (HD-CVI), High Definition Serial Digital Interface (HD-SDI), and High Definition Transport Video Interface (HD-TVI).


AHD technology was originally developed by Nextchip, a Korean design firm that makes chipsets for the video security market. It supports data transmission over both coax and unshielded twisted pair (UTP) over a maximum distance of 500 meters through the use of equalizers.


AHD can transmit uncompressed real-time images at 30 frames per second (fps) over long distances using advanced compression algorithms and signal filtering.


AHD does not support PTZ cameras, menu controls, and remote focus/zoom lens control, making it arguably less desirable than other options.


HD-SDI: Serial digital interface (SDI) was first standardized by the society of motion picture and television engineers (SMPTE) in 1989. The high definition version was released in 2010 as SMPTE 292M, where the 720P resolution is defined by SMPTE 296M and the 1080P resolution is specified in SMPTE 274M. The original bit rate for standard definition SDI was around 300 Mbps while HD-SDI is around 1.5 Gbps.


With chipsets from a number of major manufacturers including Semtech, Intersil and Texas Instruments, HD-SDI has a high degree of vendor diversity. Similar to many HD-over-coax technologies, the transmitter receives video data from the CMOS sensor as well as audio data and serializes it into an SDI format. Different forms of compression algorithms can be used along with equalizers in order to achieve longer cable reaches.


HD-CVI: Originally developed by Dahua Technology, HD-CVI can accomplish up to 500-meter transmission distances and 1080P resolution. The technology supports up to 960H analog cameras for standard definition as well as 1080P HD-SDI cameras for a wide range of compatibility. HD-CVI also has bidirectional control signals and is able to transmit both video/audio and camera control over one coaxial line. This technology is significantly more cost-effective than HD-SDI but was proprietary and only sold by Dahua until recently.


HD-TVI is an open technology developed by Techpoint, a semiconductor company. The HD-TVI 2.0 technical specification was released in 2014 and was quickly adopted by tier one video surveillance manufacturers, such as Hikvision, AVTech, IDIS, TVT and others.


The primary benefit of this technology over HD-SDI is associated with the ability to transmit over 500 meters with uncompressed HD video using cost-effective UTP coax. There is also bidirectional transmission of the control signals, allowing for more camera control flexibility.


HD-TVI and HD-CVI are similar in cost and quality of image. The main difference between the two is that HD-TVI is an open source technology open to third party vendors; while Dahua was the sole manufacturer of HD-CVI digital signal processing (DSP) chips for a few years. However, Dahua has now released the technology to select manufacturers.


This post was taken from an article L-com wrote for Security Dealer & Integrator magazine. To read the entire article click here.


A Cornucopia of Coax

October 29, 2015 at 8:00 AM


Do you love endlessly searching for coaxial products to fit your requirements? Is the highlight of your day going from one company to another to get the correct coax solution? If you answered no, we’re on the same page.  If you answered yes, we may be a little concerned.


Finding the coax products you need can be a daunting task when you have multiple coaxial applications, need multiple parts or just want the right part the first time. That’s why, when it comes to coaxial products, L-com brings more to the table than just a basic offering, we bring you a cornucopia of coax cables, bulk cable, connectors, adapters and more! Our product line includes everything to address your coax needs and if what you are looking for doesn’t exist, we can make it for you as a custom product.


We offer one of the broadest lines of off-the-shelf coaxial products for all of your 50 Ohm and 75 Ohm applications including wireless, video surveillance/CCTV, OEM, Audio and Military/Aerospace. Our coaxial product line features coaxial cables, RF connectors, RF cables, coax connectors, coax adapters, tools and other high quality coaxial products.


For wireless connectivity applications, we stock thousands of low loss 50 Ohm antenna RF cable assemblies, pigtails and bulk cable. Our inventory includes both popular and hard to find coax connectors, couplers and splitters for low-loss 50 Ohm applications for use in Wi-Fi networks.


If, for some reason, we don’t have what you need, we can make it for you. L-com can custom design cable assemblies, adapters, and almost any other connectivity product to meet your project requirements and we can build them in large or small batches. We even have a handy cable configurator that saves you time by allowing you to design and order your own custom cable assemblies online, including low-loss coaxial and RG-style coaxial cable assemblies.

When it comes to coax, our abundant product line offers everything you need in one place. Click here to see what our cornucopia of coax brings to the table.


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