Choosing the right HDMI Cables, HDMI over Ethernet, HDMI over Network UTP/STP Bandwidth Required

When choosing HDMI cables or installing HDMI Switches, HDMI over Ethernet, HDMI Extenders or any HD equipment between source and display you need to check which type of bandwidth will be needed for the Audio & Video you will be sending over the HDMI Network, otherwise digital sparkles, HDMI handshake issues and other Audio and Video problems will occur. All HDCabling HDMI Distribution equipment conforms to either HDMI v1.2 or HDMI v1.3 bandwidth specifications as explained below. HDMI cables conform to Category 1 or Category 2 cables which indicates the transmission bandwidth of the cable. In general all 720p/1080i players will work with Category 1 cables, but for future bandwidth requirements Category 2 cables are recommended. As seen below in the HDMI specifications table the HDMI v1.0 specification was already sufficient to handle Blu-ray Video & Audio (Master HD Audio and DTS TrueHD Audio excluded)

The world will most probably not see Uncompressed Full HD 1080p broadcast in the next 10 years without compression used (See massive bandwidth requirements below). Currently HDPVR / Multichoice broadcast the HD Channel at 720p/1080i and uses a compression technique called MPEG2 to reduce the amount of bandwidth required. MPEG4 is the new compression algorithm and will require about half of the bandwidth of MPEG2. Since these compressions are used and you do not see the uncompressed version of the content, artifacts and digital noise sometimes appear when watching a movie especially on darker scenes, where flames, reflections or a lot of action is present in the video. Most people regard 1080p as 1080p, but the difference in quality when screened can be substantial and some people might think it is a problem with their cables or equipment, but it may be a scene on the Blu-Ray / Broadcasted content that has been compressed too much by the compression technique used to save bandwidth.<br
The table below does a quick explanation of the different HDMI versions Video and Audio bandwidth and which equipment your need. HDMI Cabling HD Distribution equipment conforms to either v1.2 or v1.3 specifications below depending on equipment type. Our HDMI cables are all HDMI v1.3. The HDMI 1.3 specification has defined two categories of cables: Category 1 certified cables which have been tested at 74.5 MHz (1080i/720p) and Category 2 certified cables which have been tested at 340 MHz. To reduce the confusion about which cables support which video formats Category 2 cables will support all Category 1 resolutions and are recommended in general but are more expensive than Category 1 cables especially on longer distances > 5 meter.

To translate Gbit/s (Gigabits per second) and Mbit/s (Megabits per second) in the table above to Gb/s (Gigabytes / sec) and Mb/s (Megabytes / sec) we have to divide the figures in the table above by 8 since each byte has 8 bits. This translates to the table below.

Below is the table and bandwidth speeds for Ethernet / network cabling that are commonly used for extending HDMI over longer distances via Ethernet cabling. We need this table to check which type of UTP / STP cable needs to be used to reach our bandwidth requirements for the type of video and audio we will be playing between source and display.

Twisted pair cabling

In its simplest form, twisted-pair cable consists of two copper strands woven into a braid and covered with insulation.

Two types of twisted pair cable are generally recognized:

• Shielded Twisted Pair (STP);
• Unshielded Twisted-Pair (UTP ).

A cable is often made of several twisted pairs grouped together inside a protective jacket. The twisting eliminates noise (electrical interference) due to adjacent pairs or other sources (motors, relays, transformers).

Twisted pair is therefore suitable for a local network with few nodes, a limited budget and simple connectivity. However, over long distances at high data rates it does not guarantee data integrity (i.e. loss-less data transmission).

Unshielded Twisted Pair (UTP)

UTP cable complies with the 10BaseT specification. This is the most commonly used twisted pair type and the most widely used on local networks. Here are some of its characteristics:

• Maximum segment length: 100 metres
• Composition: 2 copper wires covered with insulation
• UTP Standards: determine the number of twists per foot (33 cm) of cable depending on the intended use
• UTP: collected in the EIA/TIA (Electronic Industries Association / Telecommunication Industries Association) Commercial Building Wiring Standard 568. The EIA/TIA 568 standard used UTP to create standards applicable to all sorts of spaces and cabling situations, thereby guaranteeing the public homogeneous products. These standards include five categories of UTP cables:
• Category 1: Traditional telephone cable (voice but no data transmission)
• Category 2: Data transmission up to a maximum of 4 Mbit/s (RNIS). This type of cable contains 4 twisted pairs
• Category 3: 10 Mbit/s maximum. This type of cable contains 4 twisted pairs and 3 twists per foot
• Category 4: 16 Mbit/s maximum. This type of cable contains 4 copper twisted pairs
• Category 5: 100 Mbit/s maximum. This type of cable contains 4 copper twisted pairs
• Category 5e: 1000 Mbit/s maximum. This type of cable contains 4 copper twisted pairs
• Category 6: 1000 Mbit/s maximum. This type of cable contains 4 copper twisted pairs
• Category 7: 10000 Mbit/s maximum. This type of cable contains 4 copper twisted pairs. All pairs are shielded individually.

What is the general difference between category 5e and category 6?

The general difference between category 5e and category 6 is in the transmission performance, and extension of the available bandwidth from 100 MHz for category 5e to 200 MHz for category 6. This includes better insertion loss, near end crosstalk (NEXT), return loss, and equal level far end crosstalk (ELFEXT). These improvements provide a higher signal-to-noise ratio, allowing higher reliability for current applications and higher data rates for future applications.

Will category 6 / 7 supersede category 5e?

Yes, analyst predictions and independent polls indicate that 80 to 90 percent of all new installations will be cabled with category 6. The fact that category 6 link and channel requirements are backward compatible to category 5e makes it very easy for customers to choose category 6 and supersede category 5e in their networks. Applications that worked over category 5e will work over category 6.

Most telephone installations use UTP cable. Many buildings are pre-wired for this type of installation (often in sufficient number to satisfy future requirements). If the pre-installed twisted pair is of good quality, it can be used to transfer data in a computer network. Attention must be paid, however, to the number of twists and other electrical characteristics required for quality data transmission.

UTP major problem is that it is particularly susceptible to interference (signals from one line mixing with those of another line). The only solution to this is shielding.

Shielded Twisted Pair (STP)

STP (Shielded Twisted Pair) cable uses a copper jacket that is of better quality and more protective that the jacket used for UTP cable. It contains a protective envelope between the pairs and around the pairs. In an STP cable, the copper wires of one pair are themselves twisted, which provides STP cable with excellent shielding, (in other words, better protection against interference). It also allows faster transmission over a longer distance.

How much Bandwidth to I need between my source and display ?

Several different Video / Audio streams are listed below and this guide is a maximum required for transmitting these signals. Please use this guide to determine which type of HDMI cables will suffice and which type of ethernet / network cabling you need to use when transmitting HDMI signals over ethernet / UTP / STP. This features as a guide only and if you are unsure regarding which type of cabling to use rather go for Category 2 HDMI cables for HDMI to HDMI connections and CAT6 / CAT7 cables for HDMI over network configurations. If the cable length in general is > 25 meter and there might be electrical interference nearby the cable go with STP / Shielded Twisted Pair cabling from the categories below. Specific brands of CAT5e / CAT6 and CAT7 quality also differs so rather go with the brand we sell or purchase a brand that conforms to the correct specifications.

You need to add the Video and Audio requirements in Mb/s below together to check which cabling will best suite your needs for current and future HDMI equipment you will be using. e.g. If you are using a Blu-ray player at 1080p (Most use MPEG2 compression) for Video and Dolby Digital 5.1 for Audio you will need 36Mb/s Video + 0.45Mb/s Audio = ± 37Mb/s from the table below. You then should go with Category 2 HDMI cables and CAT5e UTP/STP as a minimum(STP for less signal loss and better shielding agaist interference nearby). As a recommendation always go with one level better on ethernet cables to provide more bandwidth in feature and for distances > 25 meters choose CAT6 as a possible option since off less signal loss on longer distances.