SPECIALISED USB AND HDMI CABLES

Article by Transfer Multisort Elektronik

“Computer” cables are presently used in numerous diverse applications. They are no longer designed only for the needs of individual consumers, IT professionals and office staff, but they are also used in industrial applications to communicate with IoT devices and to connect and configure a variety of controllers based on single-board computers or other embedded systems. The field of computer cabling covers an extensive range of products including not only cables, but also adapters, extenders and various accessories. The ongoing standardisation of connectors and communication protocols will never fully eliminate the demand for cables having certain special properties, e.g. extenders that actively amplify signals to facilitate their transmission over long distances. On the other hand, we have been observing the “oversupply” phenomenon on the computer cabling market. Countless suppliers offer seemingly universal solutions, which are only sometimes subjected to random quality checks, and are often mass-imported from anonymous manufacturers willing to print any purchaser’s logo on their products. Such solutions surely cannot inspire any confidence in their reliability, especially when their reliability determines the quality of teleconferences with the company’s management board or presentations elaborated for important clients.

Fortunately, there is a small group of companies which guarantee the high quality of their product portfolio. One of them is Digitus, a European brand with long-standing market presence and specialising in computer cabling and accessories. Digitus belongs to the renowned German provider of IT solutions, ASSMANN. The Digitus products that are currently included in the TME product catalogue are a range of universal and functional solutions characterised by their durability and conformance with the latest standards. They are subjected to rigorous tests, well documented and tried-and-tested by a wide group of users.

See below for the assortment of Digitus adapters, extenders and accessories designed to support HDMI and USB interfaces.

CABLES

Firstly, we will focus on the basic USB and HDMI cables. This assortment also includes numerous adapters offered by Digitus.

HDMI cables

10-metre HDMI cable with an amplifier integrated with the plug

It can be assumed that the basic functionality offered by the HDMI interface can be achieved using the majority of currently marketed cables. However, the advantages offered by higher-quality cables supplied by Digitus become noticeable when the cables are subjected to long-term use, especially if they are to support the full range of capabilities provided by the multimedia protocol. These include, for example, transmission of the highest possible image quality (8K, i.e. UHD 4320p) with simultaneous digital audio signal transmission in the Dolby TrueHD format. Accessories without properly designed shielding, in which conductors have not been made as per the standard specifications, may result in visible interferences (especially over time). These interferences will not manifest themselves as subtly “snowy” images or minor imperfections, as is the case with analogue signals. Digital transmission interferences have much more severe impact on users, as they cause image “stuttering” or intense crackling sounds. In addition, cheap substitutes may prove unreliable when the device comes with additional functionalities/protocols included in the broad HDMI standard specification, which many users may not even be aware of. Such elements include the eARC feature (return audio signal), EDID (sending signal source metadata) or HDCP, i.e. feature preventing copying copyrighted content (used in certain devices, such as Blu-ray players).

Digitus cables are designed to take advantage of all HDMI capabilities (up to generation 2.1) and ensure long-lasting product operation. The conductors are enclosed in robust, abrasion-resistant braids, and the plugs (basic or micro format) come with solid tabs preventing connectors from damage (made of aluminium in selected models). The manufacturer supplies 1 – 30 m long cables, and the longest model comes with a signal multiplier integrated with the plug, which is supplied directly from an HDMI socket. Gold-plated contacts ensure enhanced resistance to corrosion caused by average ambient humidity. Moreover, selected models have LSZH insulation, made of halogen-free materials generating limited amounts of smoke while burning.

USB extenders and cables

Non-standard extensible USB cable designed for power supply and charging purposes

Apart from HDMI cables, there are at least two types of USB cables offered by Digitus that are worth analysing in detail, i.e. cables designed for power supply and multimedia signal transmission (see the sections below). They come in 0.7 m – 3 m length versions and are based on USB Type-C connectors. In fact, this format has become a general standard for DC power supply. This has resulted in the fact that European regulations require installing such ports in all mobile devices. Selected Digitus cables conform to the complete specification of the Power Delivery norm related to the USB-C standard, i.e. they facilitate supplying current even at the level of 5 A, at 48 V DC voltage (i.e. max. 240 W). Almost all products are rated as 3 A and 5 V DC. Note also that selected Digitus USB cables are manufactured as per the latest standard specification, i.e. USB 4.0 generation, which supports data transmission at speeds reaching 40 Gbps. In order to ensure backward compatibility, selected cables come with Apple Lightning and Micro USB plugs, and obviously USB A/B plugs.

USB-video adapters

Another, increasingly popular USB cable functionality facilitates their use for multimedia (both video and audio) signal transmission. Unfortunately, it often turns out that one of the devices (computer or monitor) is not equipped with the required port, and an adapter is necessary. To solve this issue, Digitus offers bi-directional adapters and cable-adapters. Such cables are equipped with a USB connector at one end, and a plug supporting one of the most popular standards at the other end: DisplayPort, HDMI or DVI. Such cables support digital sound and video transmission at Full HD (or even 4K) and prevent premature and costly replacement of devices. They are available in 1 m – 5 m length versions.

Cable-adapter connects a monitor with a DVI input to a USB-C port.

Digitus also offers USB video transmission cables designed as AOC, i.e. Active Optical Cables. This technology integrates plugs with optical transducers and replaces a harness made of copper conductors with glass fibre wires. This results in ensuring lossless, unidirectional multimedia data transmission over relatively long distances (10 m, 15 m or 20 m), using a cable with a diameter of just 4.8 mm. Such cables are characterised by small weight, good flexibility and full compatibility with most monitors, TVs and other receivers (e.g. AV receivers).

HDMI SIGNAL EXTENDERS

Accessory set and a compact, wireless HDMI signal relay

In numerous set-ups, video signals must be transmitted over long distances, and using a standard extender or a long cable is not always feasible. A classic example involves transmitting video to a projector or display located in another room, e.g. to display a video, run a presentation or monitor the operation of a remote controller. To this end, Digitus offers two groups of solutions, i.e. extenders with Ethernet cables (also as per the HDBaseT™ standard) or wireless relays. In the former case, if an IP connection is used for signal distribution, multimedia transmission (including lossless Full HD digital video, up to 60 Hz) can be simultaneously received by up to 253 devices. It facilitates building extensive information systems in office buildings, public utility buildings, shopping centres, etc. If data is transmitted using a LAN (IP) infrastructure, the transmission distance is, in theory, unlimited. In the case of direct connections (single, 8-conductor twisted-pair cable routed from point to point), the distance between the transmitter and the receiver can reach even 150 m (depending on the set selected).

Wireless extenders handle distances up to 50 m or even 80 m in a straight line. Here, customers can select between two types of devices. They can either be based on mains-powered relays (designed for “permanent” installation) or they can be small devices that are similar in size to a portable memory stick (see the photo), so they can be easily transported in a laptop bag. Such extenders are supplied via a USB connector (a power bank is sufficient), which makes it possible to quickly connect them to a display. This is an unquestionable advantage, as it allows a user to prepare a presentation in a conference room in a matter of moments, avoiding the hassle of handling long cables, thanks to which their computer can be placed in any location. Note also that the majority of Digitus solutions handle not only digital video and audio data transfer, but also remote control signal (IR) transmissions. For example, this functionality enables users to operate an AV receiver located in another room.