subject: Using Hdmi Extender Over Cat To Transmit Digital Video , Audio And Infrared Over Ethernet Cable. [print this page] Background: Background:
HDMI is the de facto standard for transmitting HD video and audio for consumer HDTV systems. HDMI provides pristine digital high definition video with best in class performance.
A Typical connection from HD source to HD display is a direct connection using a high quality HDMI cable. Alternatively, HDMI can be transported over ethernet CAT 5e,6 7 cables using HDMI Extenders over CAT.
What is HDMI Extender over CAT:
There are 2 basic components in the HDMI Extender over CAT: 1) Transmitter and 2) Receiver. Their functions are described below:
Transmitter: HDMI input is fed to a buffer amp and drives a RJ-45 connector at the output. The buffer amp enables driving the CAT cable.
Receiver: RJ-45 connector input is fed to a compensation circuit and drive the HDMI output connector.. The compensation circuit rectifies signal degradations incurred in transmission.
Why use ethernet CAT cables if I can use HDMI:
It is recommended that a high quality HDMI cable be used for installations whenever possible. However, there are installation scenarios/ applications where using ethernet CAT cables is practical.
For example:
Pre-installed cables available: Many homes are pre-wired with CAT cables. Therefore, it is practical to utilize the pre-installed CAT cables to transport HD video instead of installing new HDMI cables.
CAT ethernet cables are easy to terminate: Ethernet cables are available pre terminated or can be easily terminated on site with readily available tools. The advantage is that installations do not involve installing fixed length/pre-terminated HDMI cables. The installer can simply route the CAT ethernet cables from source to display and terminate with RJ-45 connectors.
Link distance:HDMI Extenders over CAT can support long link distances over CAT cables.
Infrared or SPDIF Audio transmission needed: Some HDMI extenders over cat can transport additional signals such as Infrared and Toslink Optical audio along with HDMI. This provides an easy to use cabling system for installations requiring HDMI, Infrared control and Toslink audio.
What Features to look for:
Active Drive and Compensation circuitry: Transporting high resolution HD video is challenging. It is imperative the Transmitter includes a buffer amp to drive the CAT cable and the Receiver includes compensation circuit to "correct' signal degradations incurred during transmission. Some devices may only include a "passive" transmitter unit and often can not drive longer length cables and should be avoided.
Infrared I.R. transmission: Most users will need Infrared I.R. control of the source from the viewing area. A HDMI Extender over CAT with IR transmission enable the user to send I.R. signals from the viewing area ( HDTV location) back to the Source. Typically, an I.R. receiver is connected to the Receiver unit and a IR Blaster cable is connected to the Transmitter unit and used to control the source device.
Audio Optical Toslink transmission: For users who need to integrate with pre-existing Audio receivers with only Optical inputs. Optical toslink can be transmitted over the CAT cable using some HDMI Extenders over CAT.
What type of ethernet cable should I use:
Cable Selection: It is recommended that you use the best quality cable available as shown in the table below. CAT 6 shielded and CAT 7 yields best performance and most immune to interference. CAT 6 UTP is good however may be prone to interference if cables are routed near other electrical sources or cables. CAT 5 should be avoided when possible. EIA/TIA-568-B termination (T568B) recommended. The following is brief summary of ethernet cable types vs. quality.
CAT 5 poor for short links
CAT 6 UTP good for mid links , minimal EMI interference environment.
CAT 6 shielded excellent mid to long links, where there are potential EMI interference
CAT 7 best for BEST performance
How should I connect the HDMI Extender over CAT:
Make sure the ethernet cable does not pass thru an ethernet switch/router/hub. There must be a direct connection between the Transmitter unit and Receiver unit.
Whenever possible, use a well terminated cable and a direct connection ( no patch panels, no wall plates, no couplers in between). Using a pass thru wall plate as shown below is recommended to minimize interconnections.
Do not use "punch down" terminals to terminate ethernet cables. "Punch down" terminals will degrade cable performance and should be avoided.
Avoid using in line couplers to connect 2 ethernet cables. Couplers introduce discontinuities and should be avoided.
Keep ethernet cables as straight as possible. Avoid loops and sharp bends.
Keep ethernet cables from other cables and other electrical sources to avoid interference.
