DIPOL Weekly Review – TV and SAT TV, CCTV, WLAN

A camera that shows the invisible.

Researchers at Northwestern University have built a high-resolution camera that allows you to "see" what is normally invisible. Using it, you can peek around corners, look through distracting objects such as fog, skin, or even the human skull. Their research was published on November 17 in the “Nature Communications journal”.

The camera operating principle is based on the NLoS (non-line-of-sight) technology, which is the imaging of objects outside the field of view. The new method, known as the synthetic wavelength holography, consists in indirect scattering of coherent light in the direction of invisible objects, then backscattering on the object in the return direction and being analyzed by the camera's sensors by comparison with a reference signal being simultaneously transmitted.

To accurately measure the speed of light, extremely expensive and fast detectors are needed. To eliminate these, the researchers combined light waves from two lasers and generated a synthetic light wave that can be specifically tailored for holographic imaging in different scattering scenarios. If it is possible to capture the entire light field of an object in a halotron, it will also be possible to reconstruct the object's three-dimensional shape in its entirety. This method has great potential and could allow imaging of fast-moving objects, such as a beating heart in the chest or speeding cars around a street corner.

Looking around a corner compared to imaging an organ in the human body may seem like a completely different challenge, but in reality it is not. In both situations, scattering media are involved in which the light falls on an object and scatters in such a way that you cannot directly see the image of the object. If anyone has ever lit their hand with a flashlight they must have experienced this effect. You can see a bright spot on the other side of the hand, but in theory, there should be a shadow cast by the bones and revealing their structure. Instead, the light that passes through the bones is scattered into the tissue in all directions, completely blurring the shadow image.

Over the past years, there have been many attempts at NLoS imaging to reconstruct images of hidden objects, but the methods used have typically been imperfect. The new technology eliminates the imperfections and is the first method of imaging "around the corner" and through scattering media that combines high spatial resolution, temporal resolution, a small probing area and a large angular field of view. This means that the camera can image fine features in small spaces with a high resolution, as well as hidden objects over large areas, even when the objects are moving. The camera developed by the researchers is a prototype. Its application may not be possible until 10 years from now at the earliest, however, it is undoubtedly a big leap forward in, for example, the creation of early warning systems in vehicles or in non-invasive medical imaging.

Why use the outdoor twisted pair?

Outdoor telecom cables usually have a sheath made of polyethylene (PE). This material is tougher and has greater mechanical strength than the polyvinyl chloride (PVC) used in indoor cables. What is also important, this material is much more resistant to UV rays, so the lifespan of outdoor cables exposed to sunlight is much longer compared to indoor cables operating under the same conditions.

The video below shows typical problem of using PVC-coated cable to connect an outdoor antenna with a router, when there are practically no horizontal sections on the route. The cable laid along the facade, exposed to high and low temperatures, as well as to sunlight and rain, cracks after several years at the latest. Afterwards, water gets inside, and after a short time, due to gravitational force, it "flows" down to the router. This may of course damage of the router itself and, in case of large accumulation of water in the area of the router, damage of other elements, such as furniture.

The effect of using indoor twisted pair cable on the outside of a building. Installers mitigate the effects of cable breaks by creating loops that prevent water from flowing downward, but this is an ad hoc measure. It will be more reliable to combine these measures with the use of the right kind of cabling.

DIPOL offers the following types of outdoor twisted pair cables:

Group reset and restoring factory defaults in Hikvision devices.

To quickly and effectively reset a larger number of Hikvision devices, such as DVRs, cameras, IP video intercoms etc. to factory defaults you can use the Batch Configuration application. The software is very user-friendly and, in addition to quick device reset, it offers multiple options to speed up the system configuration process, such as group updates, export of the device list, time synchronization, setting video parameters and many others.

After running the program with administrator privileges, it will automatically search for devices in the local network. After selecting, click the +Add button and enter your login details to add them to the program. After adding, select the devices and select the System Configuration -> Restore -> Complete Restoration tab from the upper bar. Once confirmed, the devices will be completely reset to factory defaults.

DDM function in SFP inserts.

DDM, or Digital Diagnostics Monitoring, is a set of functions that allows you to monitor the operation of fiber SFP modules in network switches. When a DDM-enabled insert is placed in a switch it gains access to the following insert performance parameters:

Moreover, depending on the implementation of the protocol in the switch itself, it is possible to display messages on the transmission problems and total loss of signal. DDM in connection with SNMP (Simple Network Management Protocol) allows more efficient network management and monitoring of its parameters at physical layer level. It is possible, among other things, due to possibility of defining alarm levels for individual parameters.

Installation of TERRA MR-9xx series radial multiswitches in a RACK cabinet.

The RACK board ZMD-1 R77311 front mounting assembly is a set of two brackets for mounting in a RACK cabinet. It has dedicated holes for mounting of TERRA MR-xxx multiswitches (hole spacing: height 120 mm, width 100/140/180 mm). The M5x10 bolts and nuts are included. The vertical spacing of the elements is chosen so that the cables connected to the multiswitch input connectors have enough space to maintain the minimum bending radius. It is even possible to install Signal R48602 surge protectors. The set includes eight screws with caged nuts, used to assemble the unit in the cabinet.

Recommended 802.11ax access point. The TP-LINK EAP610 N25690 access point provides a flexible, easy-to-install, manageable and secure business-class wireless network solution. It can be easily mounted to a wall or a ceiling. WlAN configuration and management are simplified through centralized software and web-based management (no need of a controller). Automatic bandwidth management and captive portal authentication make the EAP610 ideal for demanding environments such as campuses, hotels, shopping malls or offices. The device works on the 2.4 GHz and 5 GHz bands in the 802.11ax (WiFi 6)... >>>more