HDBaseT for Ultra HD Video Displays and Digital Signage
2016 年 6 月 9 日 / General
So your customer has decided to deploy HDBaseT for ultra high definition video displays and digital signage. If you're already experienced in deploying a copper cabling infrastructure for IP-based Ethernet applications like voice and data, you have little to worry about.
But it's still important to know the basics and best practices required for HDBaseT performance and error-free video transmission, and what's required when it comes to testing.
The Difference is in the Protocol
Promoted and advanced by the HDBaseT Alliance, HDBaseT is a consumer electronic and commercial connectivity standard for transmitting uncompressed HD video, audio, 100BaseT Ethernet data, power (through power over HDBaseT) and various control signals over common category copper cabling and RJ45 connectivity up to 100 meters. Sound familiar?
Although the cabling infrastructure for HDBaseT may look the same as Ethernet, it is actually based on a different protocol. While both use pulse amplitude modulation (PAM) coding technology, and HDBaseT does support an Ethernet channel, HDBaseT is not packet based data that uses Internet protocol (IP).
HDBaseT specific equipment--everything from transmitters and receivers, to projectors and displays--is certified by the HDBaseT Alliance to ensure interoperability within an HDBaseT system. An HDBaseT device connected to an Ethernet network will typically only enable its Ethernet capabilities and will not transmit audio/video.
Some Things Stay the Same
Since HDBaseT runs over the same cabling infrastructure as the LAN, it is deployed using the same best practices for cable handling and termination--everything from maintaining pair twist and not exceeding the bend radius to staying away from power sources. And just like the LAN, distance matters. HDBaseT also runs over 100 m channels.
Something else that stays the same is the fact that cable quality matters--the better the cable, the better the signal. Just like Ethernet, a higher quality cable will maintain the HDBaseT signal better over longer distances. And just like Ethernet, shielded cable is recommended for HDBaseT systems deployed in noisy interference-prone environments.
Another similarity is alien crosstalk. While HDBaseT can run over Category 5e or Category 6 cable, neither of these cables have alien crosstalk specifications. This isn't a problem for an individual HDBaseT channel. But just like bundles of cables transmitting 10GBASE-T, bundles of cables transmitting HDBaseT can be adversely impacted by alien crosstalk. That's why it is recommended to use Category 6A for installations designed to support multiple HDBaseT cables in the same pathway.
You Still Need to Test It
While there are specific tools for testing the HDBaseT application itself to ensure proper resolution, frame rate and other video specifications, the cabling infrastructure also needs to be tested--just like when deploying an IP-based LAN.
In fact, the HDBaseT Alliance specifically states that whichever cable type is deployed, it must be tested for compliance with the appropriate TIA standard. That's right--there is really nothing different about testing cables for HDBaseT versus Ethernet. If Category 6A cable is deployed for an HDBaseT system, it must be certified to meet the TIA Category 6A standard, including alien crosstalk testing--especially if you want to receive the manufacturer's warranty.
In other words, go ahead and use your DSX-5000 CableAnalyzer™ for an HDBaseT deployment. It will do exactly what you need it to do.