Good morning Guest

VGA/DVI/HDMI Installation Notes

VGA/DVI/HDMI-over-CATx Distribution products

Installation notes and FAQs 
 
 
The DataBay and Apantac ranges of AV signal distribution equipment are capable of high quality results. This guide is intended to help achieve optimum performance from the equipment by following simple guidelines and good installation practice.

Cable
The product range distributes the AV signals via various cable types. As with any installation, the type and quality of cable can have a dramatic effect on the display quality and performance. For example, a CCTV system may be installed with all manner of RG59 cable, but the resultant differences in image quality from best to worst can be huge.

Where a AV system is extended via Cat5e / Cat6 cable, we strongly recommend the use of a Low Skew cable. Skew is a measurement (normally in nanoseconds per 100m.) that measures the time delay between the first and last signal arrival in different twisted pairs. If the time difference is too large, image quality can be affected, possibly manifesting itself in bright vertical lines, ghosting, colour smudging or worst case, no image at all. Low Skew in video terms is cable with a Skew rate lower than 15nS per 100m. 
 

The following Cat-x cables should all perform well:

Belden 7988 Brilliance
Belden 7987R
Belden 1700A
Canford 31-953
Mohawk M58813
 


Environmental issues
The area surrounding an installation can also have an impact on its performance. In particular electrical noise from mains cables, fluorescent lighting or electric motors / installations, etc. could result in interference being induced into the AV cabling system and affecting its performance. The same applies to airborne radio frequency interference. Common sense and good installation practice should minimise these effects through careful cable routing, avoiding mains cables or other areas of potential interference. In areas of high susceptibility, it would be sensible to use low skew screened cables.

Display resolutions & refresh rates
Higher display resolutions and video refresh rates all require higher bandwidths and data rates. The result of the greater demands on the cable is, consequently, reduced achievable distances.
For example: A display running a resolution of 480p may happily work across a 80m. link whereas the same infrastructure running a display at 1080p may only achieve 30m.
 
FAQs

Q. What is Low Skew Cat-X cable?
A. Skew is a measurement (normally in nanoseconds) which measures signal delays between different twisted pairs in a cable. Low Skew in video terms is cable with Skew rates lower than 15nS per 100m.

Q. Can I extend the distances further than specified?
A. This could be possible by:
- Reducing the display resolutions
- Using better quality Cat-X cable
(low skew, shielded - STP or FTP)
- Using better quality video cables

Q. I’m only using a 5 metre Cat-X link cable between the transmitter and receiver, but I cannot get a picture...
A. This can occur when using short cables of maybe 5 or 10 metres with receivers that are optimised to function over much longer distances e.g. 300m. In this case either use a slightly longer Cat-X cable or use a different receiver.

Q. Can I use this system on an existing data network with hubs, switches and routers?
A. No, the Databay VGA, DVI and HDMI -over-CATx extenders and expanders will only work on a dedicated Cat-X cabled system without hubs, routers or switches. 

 Q. I’m using a short range HDMI non-powered receiver (p/n HDMI-HR), but cannot see an image; why?
A. Some flat panel monitors use a slightly non-standard input which requires power at the HDMI input socket to function correctly. Some Samsung and Goodmans monitors are known to suffer from this issue (there may be others). Use a powered receiver such as the ET-HC0101-R if this is an issue.

Q. How many levels of cascading can be achieved on HDMI?
A. Normally two is recommended, although at lower resolutions and with good quality cables further cascading may be possible.

Q. Can I use stranded Cat-X patch cord?
A. Stranded Cat-X cable is not recommended – use solid installation Cat-X cable for best results.

Q. If I ‘mix’ transmitters and receivers of different distance capabilities (e.g. AVE-301T 300m and the receiver from the AVE-M180TR 180m), what is the maximum distance achievable?
A. In all such cases you are limited to the distance of the shortest device (in this case 180m).

Q. How should I wire the RJ-45 connectors to the Cat-X cable?
A. The cable should be terminated to the EIA 568B specifications: