- What are Twisted Pair products?
Twisted pair products are the electronic signal conversion devices that are used to adapt common A/V signal types, including video, audio, and control signals for distribution over standard Category-type twisted pair cabling. The near-ubiquitous use of low cost CAT 5 UTP – unshielded twisted pair - cable has created an interest in the transmission of video and audio programming using this type of cable infrastructure. Sending AV over CAT5 UTP is an excellent alternative to using regular coaxial cable; signals can be sent longer distances with less interference at a lower cost.
Extron manufactures a comprehensive family of twisted pair transmitters, receivers, distribution amplifiers, matrix switchers, and cabling. Our product offerings enable integrators to develop twisted pair A/V systems for any application, from the simplest to the most complex.
Twisted pair signal transmission supports the full range of A/V signals, including RGBHV, RGBS, RGsB, RsGsBs, component video, S-video, composite video, audio, and RS-232 control signals. Almost any signal type can be adapted for use with twisted pair cable by selecting the appropriate Extron twisted pair transmitter and receiver combination.
- Is twisted pair transmission the same as streaming audio/video over data cable?
No. Extron twisted pair products are not compatible with Ethernet/LAN applications. The transmission of A/V signals over CAT 5 UTP requires a dedicated cable that is completely separate from the data network.
- What are the differences among the different Extron twisted pair product categories?
Extron manufactures four series of products for twisted pair transmission of video, along with audio or RS-232 signals. Some features are common across all products while others may be unique to a particular series.
Our VT- VGA Series is the most economical and compact series of transmitters and receivers for distribution of RGB video signals.
The MTP Series is a versatile family of economical and compact mini twisted pair transmitters, receivers, distribution amplifiers, switchers, and matrix switchers for distributing a wide range of video resolutions and signal types — including composite video, S-video, component video, and high resolution computer-video — along with audio or RS-232 control signals.
The TP Series offers the highest transmission distance for high resolution video, and consists of transmitters, receivers, distribution amplifiers, and switchers capable of handling RGBHV, RGBS, RGsB, S-video, component video, and composite video, along with stereo audio signals.
- When should I use twisted pair products rather than coax or fiber cabling?
The low cost, light weight, and fast installation characteristics of CAT 5 UTP cable provide the primary motivation for its use in place of traditional coaxial cable for A/V applications.
Twisted pair products are useful alternatives in many applications, such as:
- Where there is limited space for conduit
- When signal integrity must be maintained over long cable runs
- In environments with an existing CAT 5, 5e, or 6 infrastructure
- For retrofits of A/V systems in historical buildings
- When aesthetics are a concern, and there is no space to hide bulky coaxial cable
- In temporary installations
For a more detailed discussion on the application and benefits of twisted pair cabling, we provide two white papers: "Sending A/V Signals Over Twisted Pair Cable: An Introduction", and "Sending A/V Signals Over Twisted Pair Cabling: Optimizing Performance."
- What is "skew?"
In twisted pair video systems, skew is a distortion in the image caused by the late arrival of one or more of the color signals. The delayed color signal is shifted to the right of the other colors in the image, resulting in very poor image quality that can cause viewer fatigue.
Interestingly, the source of skew is the cable itself. Data grade twisted pair cable was developed for computer networks where the main concern is not skew, but crosstalk. Ethernet networks consist of two signals, transmit and receive, running long distances in close proximity. To minimize the crosstalk between individual twisted pairs, the rate of twist is varied among the pairs of wire. This has a side effect of making the twisted pairs vary in length. The pairs with more twist per inch will have a longer length and signals sent down each pair will arrive at the receiver at different times. Computers have little trouble resolving this time differential, but high resolution video systems are less forgiving.
Skew is not a problem when UTP cable is used for composite video or S-video signals, because the signals are sent on a single pair of wires. High resolution video signals, on the other hand, are subject to skew, particularly at long distances, because the transmitter processes the signal and sends each color down a separate pair.
Extron offers two ways of solving the problem of skew: Enhanced Skew-Free™ A/V UTP Cable and an electronic skew delay equalizer technology that's built into some of our twisted pair products. Extron's skew delay equalizer technology uses a time delay circuit on each color input that can be independently adjusted from 0 to 39 nanoseconds, improving image quality while maintaining full signal integrity.
- What is Extron Enhanced Skew-Free A/V UTP Cable?
The best way to handle skew is to keep it out of the system altogether. And the best way to do that is install a twisted pair cable specifically designed for video transmission, like Extron Enhanced Skew-Free A/V UTP Cable.
With our Enhanced Skew-Free cable, the length of each twisted pair is uniform so the red, green, and blue signals arrive at the receiver simultaneously. This cable is comprised of four, color-coded twisted pairs of 23 AWG wires and can be terminated with RJ-45 connectors.
The plenum version of the Extron Enhanced Skew-Free A/V UTP Cable has a plenum-rated jacket constructed with special fire protection agents for use in applications where CL2P - National Electric Code cable is required. Plenum cable can be run through open air spaces, eliminating the need for conduit and reducing installation costs.
- What is the proper termination for Extron Enhanced Skew-Free A/V UTP Cable?
We recommend T568A termination that corresponds with Cat 5 UTP cable. We support various twisted pair cable standards, including CAT 5, 5e, or 6.