Follow These Steps for HDBaseT and HDMI Testing
Installers today are managing an increasingly complex web of signals, cables, sources and destinations, all of which require thorough testing to verify the quality and integrity of signals moving through the AV infrastructure. In an HDBaseT system, testing the entire cabling and wiring infrastructure is paramount to ensuring high-quality transmission with signal drops and loss of information.
The HDBaseT architecture today virtually always has an HDMI interface from the transmitting source device, such as Blu-ray player or Apple TV. These HDMI signals are transmitted over HDBaseT to a receiving device that reconstructs the HDMI signal before transmitting it to the sink device, typically a projector or display. The interface on the HDBaseT chipset is pure HDMI, meaning that seamless interoperability between the two is essential for any transmission.
Know Your System
Installers tend to put heavy focus on the HDBaseT element, ensuring that the bandwidth and stability exists to carry a high-resolution 4K signal over the extending medium. This is indeed important. However, this focus tends to overshadow assurance that the HDMI cables can support the same.
Testing the cable itself will identify both common and advanced issues. For example, one increasingly common problem is the reduction of shielded wire from within the cable. HDMI cables have 19 standard conductors for video, audio, Ethernet and data moving over twisted pairs of wiring inside the cable. Testing for the presence of shielded wires inside the cable will help to identify the supported HDMI spec, and is very important in the testing phase.
That is especially important given the transition to HDMI 2.0, was overwhelmingly driven by the urge for more bandwidth to support higher resolution signals. Many cables on the market today are still limited to 1080p and 4K 4:2:0. On very short transmissions, the viewer will still receive and see a 4K image, but this will fail on longer runs. A quick 20-to-30 second test will help determine the capabilities to carry HDMI 2.0/1.4/1.2 signals.
Test Early and Often
Integrators are in the best position when able to test the infrastructure at the point of wiring the project. A large majority of projects still rely on test systems that can only be brought in at the final installation stages. The disadvantage is clear: The wiring is complete, and if there are missing signals or a low quality connector terminations, it means pulling out all the cable and starting over hoping for the best.
Today’s more diverse, portable test devices will help installers verify signal presence and integrity up front via a variety of key parameters, including:
- The maximum overhead presence to enable carriage of high-resolution signals over HDBaseT (300 Mbps)
- Activation of links to transmit through the cable, even without a source or sink to receive the signal
- The quality of transmission on the uplink (much higher bandwidth) and also the downlink
- Improper terminations or crimps that cause faults through the twisted pair wires
These and other problems can be identified and fixed on the spot, without the need to bring in a 4K display or projectors to confirm and evaluate the link. Upon confirming the integrity of all important performance parameters at the wiring stage, the end components can be installed with confidence that the signals and quality will hold.
These concepts just scratch the surface, as there are many other parameters to test and certify throughout the HDBaseT system. Testing these systems at the earliest possible stage will reduce installation time, re-wiring, labor and other headaches that can also increase labor costs along the way.
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