TV-SAT, CCTV, WLAN Dipol Weekly Review

Rings will turn gestures into words.

Researchers in South Korea have developed a new real-time sign language translation system that could significantly facilitate communication between deaf and hearing people. The technology is based on a solution called WRSLT (Wireless Ring-type Sign Language Translator), a set of seven wireless rings worn on selected fingers of both hands. Each is equipped with a miniature accelerometer that records hand movements, finger orientation and gesture dynamics, and the collected data is transmitted via Bluetooth to a smartphone or computer, where artificial intelligence converts it into text. Unlike previous solutions based on heavy gloves or wired sensors, the system allows for natural, free-flowing blinking without movement restrictions.

Sign language is not a simple collection of gestures, but a full-fledged language with its own grammar and syntax, and there are more than 300 varieties worldwide, further complicating the creation of a universal interpreter. WRSLT has been tested to recognise both American Sign Language (ASL) and International Sign Language (ISL), achieving around 88% success rate in recognising words, even in users who have not participated in the system's training. This means that the model can, to some extent, cope with differences in the way people make gestures, which has been one of the key challenges in this type of technology.

Although the current version of the system includes about 100 words for ASL and 100 for ISL, the researchers plan further developments including increasing the vocabulary, support for more sign languages and miniaturisation of the devices. The results are promising, but not ideal - in practical communication, even a margin of error of several per cent can lead to misunderstandings, so the technology is not yet a replacement for sign language interpreters, but could become an important support or auxiliary tool for them. If further development is successful, the seven smart rings could become one of the first systems to realistically bring sign language interpreting to the level of widely available, everyday technology.

Surveillance system based on DS-9632NI-M8 NVR and EasyIP 4.0+ cameras.

The diagram below shows a surveillance system based on Hikvision's state-of-the-art 32-channel DS-9632NI-M8 K22360 IP NVR and EasyIP 4.0+ cameras, equipped with the latest algorithms to support analytical functions. The NVR used has 8 SATA ports, each of which can support hard drives of up to 16TB. Support for RAID (0, 1, 5, 6, 10) allows to protect the system against loss of recordings in case of disk failure. Two Ethernet ports allow the camera network to be separated from the network used to operate the NVR.

To the NVR, via a 24-port Ultipower 2224af N29987 PoE switch with a total power budget of 370 W, 8 DS-2CD2047G3-LI2UY/SL K03215 cameras with 4 Mpix resolution and 14 DS-2CD2087G3-LI2UY/SL K03414 cameras with 8 Mpix resolution are connected. The cameras have lenses with a fixed focal length of 2.8 mm and a wide angle of view. Thanks to the advanced technologies used in the cameras, the identification efficiency and functionality of the entire system is very high. Thanks to ColorVu 3.0 technology, which uses the Hik AI-ISP signal processor based on artificial intelligence and 3D LUT colour correction technology, the image can be observed and recorded in colour mode around the clock while retaining important identification details. AcuSense 2.0 technology, which is perimeter protection with human/vehicle object filtering, together with the AcuSerch function, allows even better false alarm filtering and fast search for objects of interest. With Audio 2.0 and a 2-microphone design for excellent noise reduction, the cameras have excellent audio quality in a variety of application scenarios. The built-in loudspeaker and strobe light, provide active and effective deterrence of intruders through audio messages and light signalling when a user-defined event occurs.

Multiswitch installation TERRA.

In one of the multi-family buildings in a small town in the Lesser Poland province, there was made a group antenna installation based on TERRA equipment. The installation consisted of MV-924L R70874 multiswitches, SA-91L R70901 broadband amplifier, SD-915 R70525 taps, and PA-420T R82516 channel amplifier. In this way, the developer has provided an FM/DAB+ radio signal, a DVB-T2 digital terrestrial TV signal and a signal from two DVB-S/S2 satellite positions for a total of 48 premises.

The system is based on two TERRA MV-924L R70874 multiswitches working in a bus system, designed to distribute radio/DVB-T2 and DVB-S/S2 signals to each of the 24 outputs of the MV-924L R70874 multiswitch. The radio/DAB+ signal and the signal from the terrestrial TV antenna were fed to the PA-420T R82516 channel amplifier, which made it possible to filter and equalize the levels of the individual DVB-T2 multiplexes. The signal from a satellite dish (two QUATRO LNBs), using 8 coaxial cables and maintaining the correct order of polarization and bands according to the VL, HL, VH, and HH symbols, was fed to the SA-91L R70901 amplifier (to compensate the losses of the bus and equalize the levels of SAT signals before further distribution to multiswitches). Measurements of the antenna installation then resulted in signal levels between 60-80 dBµV at the subscriber outlets.

How to check the correctness of a completed fibre optic splice?

If the installer ensures that each of the steps preceding the fibre splice through the splicing machine is carried out correctly, the risk of a failed splice is negligible. These include: arc calibration, proper cleaning and trimming of the fibres and, often ignored but no less important, cleaning of the fibre cutter and the splicer itself. Often, however, installers would like to increase their confidence that the weld they have made is the correct joint. This is particularly important in situations where any services are started on the completed joint at a later stage.

Verification of the correctness of a splice can begin at the splicing process itself, involving the generation of an electric arc which manifests itself by a flare on the screen, should proceed uniformly. Any additional spot flares may be the consequence of a badly cut or dirty fibre and may adversely affect the splice. If these occur, look closely at the fibre splice area on the screen - if any dark discolouration appears, it may make sense to repeat the whole process. Keep in mind, however, that splicing fibres of different standards (with different refractive indices) may be associated with the appearance of a dark vertical line at the splice site, which does not affect attenuation or transmission in any way.

The estimated attenuation given by the splicer should be regarded as additional information and of no great importance - the rule of thumb here is - if the splicer says it is wrong, repeat the splicing, if it says it is right, look at the fibre splice point anyway.
If the splicing process itself has not aroused our suspicions, we can additionally verify the correctness of its execution with the help of the VFL visual fault locator. This can be done immediately after the fibres have been spliced - in which case any light leakage is practically unseen of with a proper splice and after the splice has been protected with a heat-shrinkable splice protector - in which case slight light leaks are relatively common. Their cause lies in the imperfection of the light source and the micro-bends and stresses that occur when the sheath shrinks on the fibre. We can try to compensate for these effects by changing the casings or altering the parameters in the casing sealing programme. It is worth knowing, however, that such subtle leakage from the VFL does not affect the transmission parameters of the weld itself. However, intense, pinpoint leaks that may be indicative of weld fracture cannot be ignored.

However, many installers would like to obtain quantifiable data proving the correctness of the connection made. They equip themselves with a measuring set: a power meter and a light source. Unfortunately, the transmission measurement method does not allow the measurement of a single splice - it gives information about the attenuation of the entire line inserted between the measuring devices, including the connectors.

The only way to measure splice attenuation is to use an OTDR reflectometer. Here too, however, its purchasers may be disappointed as this measurement is limited in many situations. In a typical situation, where the termination of a fibre optic line is implemented in the form of a spliced pigtail, the reflectometric measurement will take into account the total attenuation of the splice and the connector. Only top-class reflectometers are able (and not always) to distinguish between events 1 m apart. As a rule, however, the splice will fall into the so-called dead zone behind the joint and its attenuation will be added to the joint attenuation. It will be more likely to register a splice somewhere in the middle of the measured line - away from connectors or adapters, although even in this situation one should be aware of the fact that the attenuation of a good splice of 0.01 - 0.03 dB is below the noise threshold of popular, cheap reflectometers, so such connections will also remain invisible to the measurer.

In summary, measuring the attenuation of a single splice is neither an easy task nor a necessary one. The installer should focus on the correct execution of the splicing process and any measurements should take into account the entire installation being carried out.

Twisted-pair cable – marking.

Twisted-pair is a signal cable type used to transmit information over telecommunications links and computer networks. Currently it is most often used in analog telephony and in Ethernet networks. It is made up of one or more pairs of conductors twisted together. The twist is intended to eliminate the influence of electromagnetic interference and mutual interference, so called crosstalk.

The description method of twisted-pair cable is provided by ISO/IEC 11801:2002. According to the information provided, the cable description should follow the xx/yyTP syntax where yy denotes a single pair of conductors in the cable, and symbol xx refers to the entire cable.

The xx and yy symbols can be as follows:

• U – unshielded
• F – foiled
• S – shielded
• SF shielded and foiled

How to connect an IP camera when no suitable cabling is available?

The installation of cameras or other IP PoE devices in locations where only 2 wires are available for transmission and power supply and it is not possible or cost-effective to replace the existing cabling can be carried out using the special ATTE ETH-2wire-A-SET J2843 converters.

The ETH-2wire-A-TX transmitter is powered from any PoE switch (RJ45 port) and then, using 2 cables, allows bi-directional network communication and power to the ETH-2wire-A-RX receiver together with the PoE IP camera. The LAN output port operates according to the 802.3af/at/bt standard. Optionally, the devices can be powered via POWER screw connectors.

The maximum cable length in the 2wire path is 800 m (for one pair of UTP cat. 5e cable). The maximum range of data transmission and PoE power supply depends on the type, length and cross-section of the cables used. The stability of transmission is also affected by the presence of other cables in the cable route and additional intermediate connections. The best parameters and the longest transmission range can be obtained by using two single twisted-pair cables, e.g. one pair of twisted-pair UTP cable.
A camera or other PoE receiver can be connected to the RJ45 port of the ETH-2wire-A-RX module at the end of the line.

Which Hikvision video door entry system to choose: 2-Wire IP, 2-Wire HD or maybe IP? Hikvision currently offers three video door entry systems: 2-Wire IP, 2-Wire HD and an IP system. The choice of the right system for a customer can be dictated by two factors which include: functionality and the type of communication bus between devices...>>> more