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

In the US, 8 Gbps for an average Joe.

Google Fiber, which provides fibre optic services in the United States, has announced that West Des Moines (Iowa) and Mesa (Arizona) are the two cities where customers can enjoy ultra-fast Internet access at 8 Gbps What is more, the connections offered are symmetrical, i.e. the speed of sending and receiving data can be the same. Google bases its service primarily on XGS-PON technology. The eight-gigabit internet is dedicated to professionals working from home (data scientists or engineers working on virtual machines in the data cloud). Of course, transmission speeds come at a price. The monthly fee for an 8-gigabit service is US$150. The average internet speed in the US is 198 Mbps.

Internet connections around the world continue to accelerate, especially as countries prioritise and improve mobile and fixed broadband networks. Nowhere is this more evident than in speedtest.net which tracks internet speeds by country. Average mobile internet speeds around the world have increased by 17% over the past year, while fixed speeds have increased by as much as 28%. The fastest fixed broadband speed in the Speedtest Global Index (February 2023 data) boasts Singapore (237.15 Mbps). Just behind are China (226.77 Mbps) and Monaco (226.03 Mbps).

What is PoE?

PoE (Power over Ethernet) is the name of a range of methods that allow network equipment to be powered via a twisted pair cable while transmitting data. It is possible to power devices such as cameras, telephones, switches, access points, etc. In 2003, the IEEE established the 802.3af PoE power standard, which was upgraded to 802.3at in 2009. It distinguishes between type one (the earlier 802.3af) and type two with a transmitted maximum power of 30 watts. It offers the possibility of almost doubling the power of the powered devices. As a result, cameras with powerful IR illuminators, IP telephones or network printers can be powered using twisted-pair cable.

Key PoE features:

• transmission of power and data over a single cable reduces cabling and installation costs
• guaranteed minimum range of 100 m with appropriate cabling
• high security due to low voltage transmission and link and device testing procedures
• protection against voltage connection to non-standard devices
• ease of installation
• newer standards are backward compatible.

The PoE standard defines 2 ways of transmitting power:

• option A – power sent together with data on pairs 1/2 and 3/6
• option B – power is sent over free pairs 4/5 and 7/8

Radial multiswitch system.

MR multiswitches from the TERRA MR series have up to 32 outputs and therefore allow building systems with up to 32 outlets on a single device. Such a TV network ensures trouble-free distribution of digital signals, both in DVB-S/S2 standard (satellite) and DVB-T2 standard (digital terrestrial TV). Such networks, known as radial or star networks, are the simplest type of system and generally do not require prior design. However, to be safe, a signal attenuation balance should be performed for the shortest and longest signal paths.

Control of relays in the IP Villa 2 gen. door/gate station with external buttons.

Video intercom door/gate stations IP Villa 2nd generation (except for DS-KV6113-WPE1 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. Those inputs are often used for the installation of local opening buttons, mounted at a safe distance so that they cannot be reached from outside the fence. The solution can open the wicket without a key, if no movable handle or knob is installed on the inner side. The gate can open quickly without the need for a remote control.

How to repair broken optical fiber?

DAC (Direct Access Cables) make a popular group of fiber optic cables that can be laid directly in the ground, without the need for additional protective conduits. These cables are used in practically every kind of fiber optic systems, from local monitoring systems to operator applications, most often as the "last mile" section, i.e. at the direct customer connection.

DAC cables can be damaged (ruptured) due to earth works carried out in the area or spontaneous earth pressure (landslides, freezing of the ground) that exceeds strength parameters of the cable.

It is best to replace the damaged cable. If it is not possible ends of the broken cable can be joined by splicing a piece of new cable in between. Of course, two couplers have to be used to secure the connection point. These couplers should be as tight as possible. A good practice is to use more seals in addition to those offered by default.

The picture below shows an example using a repair coupler L56040 to connect two dual-fiber DAC cables. The coupler has a rubber seal and a bolted cover to ensure a high tightness. It is advisable to protect the rubber covers on the cable entries, especially when using cables with diameters below 5 mm.

Building a house? Think of fiber optic. When designing or building a house, a lot is said about proper planning of cabling for low-current systems. However, laying the right cables outside the house at an early stage is often forgotten. Usually, apart from power cables, these include twisted-pair cables (e.g. for video intercom, surveillance cameras, intelligent house system elements etc.).
At the stage of construction works, it is also good to think about burying an optical fiber in the ground, which in the future can be used by the Internet provider...>>>more