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

Robots in the service of the New York Police Department.

Three new high-tech police devices were unveiled in New York. One of the devices is a remote-controlled, highly mobile K-9 robot ("Digidog," or digital dog). It will be tasked with assessing high-risk situations. It is expected to increase the safety of "ordinary" police officers.

The StarChase system will be used to track vehicles using a GPS transmitter fired from a specially designed weapon. Police will then be able to track the vehicle without jeopardizing public safety as well as the officers, as is the case with typical chases.

The third component will be an autonomous K5 ASR (Autonomous Security Robot). It will conduct automated patrol at subway stations using artificial intelligence algorithms to analyze data. In case of an emergency, it will notify the command center.

The New York Police Department stresses that the implementation of modern technologies is done with full respect for the privacy of citizens. For this reason, neither the robot-dog nor the K5 will be equipped with face recognition technology.

ALCAD headend.

A headend is a main device or a group of devices dedicated to facilities and institutions which require a central management of the channels available through the tv system. In addition to the headend consisting of modules according to the installer choice (transmodulators, amplifiers, optical transmitters, IP streamers) for receiving, converting the TV signals, the system comprises also the antenna assembly (satellite antennas, terrestrial TV and FM antennas). No need to use more receivers (e.g. satellite receivers) for TVs, which makes this solution particularly attractive for hotels, guesthouses, apartments and hospitals.

Headends distributing satellite programs converted to digital DVB-T/C format are still the most popular solution used in many hotels. Satellite channels can be an addition to the terrestrial television programs or be the only part of the package offered. DIPOL's offering has been expanded by two new transmodulator models: TMS-214 R82614 and TMS-204 R82616 by ALCAD.

Lightning – protection of signal paths – part 1.

Home electronic devices are exposed to current pulses induced in long cables. It does not take a direct lightning strike – a high-potential charge accumulating before or during incoming thunderstorms, causes damage to signal path equipment. If a surge occurs, for example, from the side of the antenna system, the head of the TV receiver or satellite receiver can be damaged. To protect equipment from these phenomena, there are 75 Ohm signal path surge protectors R48602. Other devices are used to protect CCTV signal paths.

Damage to a computer, TV set, or other device can occur as a result of a surge that has occurred in the power grid. Then usually the fuse and/or varistor are damaged, and sometimes even the entire power supply. An effective protection in such a situation is the ACAR 504WF RACK P1322.

Do multimode optical fibers make sense in LAN and CCTV networks?

Despite the huge popularity of single-mode fiber optics, the multimode fibers are still on the market and are used in selected applications. In theory, the multimode fibers are considered "less future-proof" – on short and medium distances they are not able to match single mode fibers in terms of throughput, while on distances longer than 2 km they are not used at all due to the phenomenon of so called modal dispersion. What is more, it turns out that multi-mode cables, despite their capacity limitations, are more expensive than single-mode cables. This is due to the fact that multimode fiber core, having gradient structure (refractive index changes and is not homogeneous like in single mode fiber core) is more complex and therefore more expensive to manufacture. So why use multimode fibres?

Oddly enough, multimode cabling is often used in server rooms to connect cabinets containing operator equipment. Special lasers and the latest standards of multimode fibers (OM4, OM5) work well there for high throughput transmissions on short distances. Moreover, when extending systems implemented a few or more years ago, installers often decide to use the same type of cabling – there is no point in changing it if it works.

Other reasons for choosing multimode cables include popular opinion that they are easier to splice (due to larger core). This ceased to hold true long ago – in the era of precision core centering splicer, the size the core no longer matters. According to other theories, multimode cables should be used for short distances and single-mode cables for long distances (> 2 km). This is no longer true either in the era when the single-mode devices offered can operate without overdriving on links of any length.

Use of cabling with multimode fibers seems to be reasonable when the system is installed in difficult environmental conditions, e.g. in industrial facilities where there is a risk of exposure to dust or dirt. A larger core of a multimode fiber is beneficial here – the same contamination (see figure above) will have a much greater negative impact on transmission in a single mode fiber (9 μm core) than in the multimode fiber (50 μm core). This difference may not become apparent in fiber splicing, where the operator cares for cleanliness and reduces the effect of external factors. However, it may be important in a switchgear and when connecting, disconnecting or rewiring equipment, if the installer fails to properly clean the ferrule face of the connector.

Relay control in the IP Villa 2 gen. door/gate station with external buttons Video intercom door/gate stations IP Villa 2 generacji (except for DS-KV6113-WPE1 and DS-KV6103-PE1), have 2 independently triggered built-in relays, which enable the control of e.g. a wicket or an entrance gate. By default, the second relay in the door/gate station is off and should be activated with the iVMS-4200 app or via a web browser. Those outputs can be triggered using the iVMS-4200 PC client application, indoor stations or after shorting to ground (GND) of AIN4 (DOOR2 relay activation) and AIN3 (DOOR1 relay activation) inputs...>>>more