No. 23/2008 (June 16, 2008)
Mesh - community networks of the future? Mesh networks differ from other networks in architecture - the component parts can connect to a number of neighbor nodes. It allows for continuous connections and reconfiguration around broken or blocked paths by jumping from node to node until the destination is reached.
The main features of wireless mesh networks:
The main features of wireless mesh networks:
- dynamically arranged connections - routes of packets depend on the state and work load of individual nodes,
- due to switching between the nodes - the risk of disruption of data transmission is considerably lower than in the case of star-shape architecture,
- possibility of quicker transmission thanks to lack of a central node,
- easy expansion by adding new nodes,
- new nodes can be installed in any places where they can communicate with other nodes and power supply is available.
So far, there is no final standard for this kind of wireless networks, but the work is on track since 2003 (the proposals were submitted to a vote in 2005). The result is IEEE 802.11s - a draft IEEE 802.11 amendment for mesh networking. Lack of accepted standard is the reason that mass development of the networks is a matter of time. This kind of solution is often used for applications requiring good network coverage and high reliability, where wired systems are not available or feasible.
A proposal for integrated wireless infrastructure in metropolitan areas
Do you recognize this building? When one of the outer walls collapsed, on the stopgap facade there were immediately installed CCTV cameras. The building was erected during the first years of WWII and opened on January 15, 1943. It is the largest traditional office building (not a skyscraper). It houses about 26,000 personnel. The building has five sides, five stories above ground (plus two basement levels), and five ring corridors per floor with a total of 17.5 miles (28 km) of corridors. Despite this, it is possible to walk the route between any points within 7 minutes. (Source: Wikipedia)
Modulators - quality has its price. Many customers prefer to buy cheap modulators. They do not pay adequate attention to the parameters that decide on usefulness for a specific application.
In simple installations, e.g. in home, to send satellite signal to another room, it is enough to use Signal Classic R95176.
In the case of several or so outlets (e.g. in larger houses, in installations for several neighbors etc.) the proper choice is one of the following modulators: MT-22P R871722 (VHF), MT-21P R871721 (UHF), or MT-27P R871727 (VHF &UHF).
In large installations the output signal levels of the modulators used have to be high enough - there should be used MT-29 R871729 (100 dBuV), or one of the following modulators: MT-21P R871721, MT-22P R871722, MT-27P R871727 (together with a set of channel amplifiers - ZG-401/601). The latter solution allows to gain up to 123 dB for every channel, including the terrestrial ones. Such a level at the input of the distribution system is suitable for supplying signal to even 200 outlets, without employing additional building amplifiers.
In multichannel networks (small number of unused channels), one has to use VSB modulators, MT-30A R871731 or MT-30C R871733 (stereo). They allow to utilize adjacent channels (to those being used for distribution of TV programs or other video signals).
In simple installations, e.g. in home, to send satellite signal to another room, it is enough to use Signal Classic R95176.
In the case of several or so outlets (e.g. in larger houses, in installations for several neighbors etc.) the proper choice is one of the following modulators: MT-22P R871722 (VHF), MT-21P R871721 (UHF), or MT-27P R871727 (VHF &UHF).
In large installations the output signal levels of the modulators used have to be high enough - there should be used MT-29 R871729 (100 dBuV), or one of the following modulators: MT-21P R871721, MT-22P R871722, MT-27P R871727 (together with a set of channel amplifiers - ZG-401/601). The latter solution allows to gain up to 123 dB for every channel, including the terrestrial ones. Such a level at the input of the distribution system is suitable for supplying signal to even 200 outlets, without employing additional building amplifiers.
In multichannel networks (small number of unused channels), one has to use VSB modulators, MT-30A R871731 or MT-30C R871733 (stereo). They allow to utilize adjacent channels (to those being used for distribution of TV programs or other video signals).
ULTIMAX - DVRs for demanding customers - maps in remote client software. Distributed video surveillance systems and systems with a large number of cameras should enable the operator to easily locate the camera capturing the image, or the sequence of cameras that follow a moving object. Camera names or numbers are in such systems inadequate for effective operation.
The map function solves the problem perfectly. It allows to import maps/plans of monitored areas (bmp files) that are the background for camera symbols associated with individual cameras. Clicking on a camera symbol, the operator displays its image in one of additional windows in the lower part of the screen, together with camera name and the name of cooperating DVR.
The maps/plans can create a hierarchical structure, e.g. from the plan of a development it is possible to pass to the plan of the building in question. The map function is often used in ULTIMAX DVRs that can be easily integrated due to effective network software. The software allows to manage large systems with a great number of deployed devices - DVRs, IP cameras, video servers.
The map function solves the problem perfectly. It allows to import maps/plans of monitored areas (bmp files) that are the background for camera symbols associated with individual cameras. Clicking on a camera symbol, the operator displays its image in one of additional windows in the lower part of the screen, together with camera name and the name of cooperating DVR.
The maps/plans can create a hierarchical structure, e.g. from the plan of a development it is possible to pass to the plan of the building in question. The map function is often used in ULTIMAX DVRs that can be easily integrated due to effective network software. The software allows to manage large systems with a great number of deployed devices - DVRs, IP cameras, video servers.
"Map" - a very useful function embedded in remote client software of ULTIMAX DVRs
New functions and lower prices - PiXORD cameras. The manufacturer of CCTV cameras and video servers - PiXORD - has issued new firmware for some cameras. The firmware is available for the following cameras P405 K1133, P405W K1134, P405M K1135, P410 K1231 and P412 K1331, extending their functionality by:
- Dual Stream,
- support of Universal Plug and Play,
- support of recording on SD card, sending JPEG files to FTP server or email address after motion detection.
Additionally, the cameras are available at new, lower prices. All the models being currently offered by DIPOL are equipped with the new functions. The customers who bought the cameras before the update can now download the new firmware.
IP video surveillance in low light. ACTi has recently launched many new IP CCTV devices. Among them there are ACM-4100 K1501 and ACM-5711 K1502 cameras. The cameras have been equipped with "Sense up" function that allows to operate the camera in low light without use of mechanically driven IR filter.
The K1501 camera can be used in stores, offices etc., the K1502 model is suitable for outdoor operation (in M5406 housing). It is important that all ACTi devices can be integrated by NVR software that is included with every piece of equipment, or by NUUO K3108 and Alnet Netstation K3208 systems.
The K1501 camera can be used in stores, offices etc., the K1502 model is suitable for outdoor operation (in M5406 housing). It is important that all ACTi devices can be integrated by NVR software that is included with every piece of equipment, or by NUUO K3108 and Alnet Netstation K3208 systems.
The camera ACTi ACM-4100 K1501 | The camera ACTi ACM-5711 K1502 |
Change of default passwords - defense against hackers. In the Internet there can be found programs that allow to log in to network devices using default user names and passwords (e.g.to routers). They enable the potential offender to reconfigure the device and connect with a false DNS gateway. In this case the Internet connection will function normally, but all the information will pass through the server determined by the hacker.
It is a real threat to the user of the device - e.g. risk of intercepting bank information.
That's why when installing such a device it is indispensable to change the default passwords. In TP-Link routers the default parameters are: User name - admin; Old password: admin. The new user name and password have to be remembered or written down. When forgotten or lost - the user can restore the default settings by resetting the device.
In TP-Link devices the procedure is to be performed in the System Tools >> Password submenu.
It is a real threat to the user of the device - e.g. risk of intercepting bank information.
That's why when installing such a device it is indispensable to change the default passwords. In TP-Link routers the default parameters are: User name - admin; Old password: admin. The new user name and password have to be remembered or written down. When forgotten or lost - the user can restore the default settings by resetting the device.
In TP-Link devices the procedure is to be performed in the System Tools >> Password submenu.
User name / password window
Pentagon - Arlington, Virginia. "Exactly 60 years to the day after the groundbreaking ceremony, the September 11, 2001 attacks occurred. American Airlines Flight 77 crashed into the west side of the Pentagon after being hijacked, killing all aboard as well as over a hundred people within the Pentagon. The flight penetrated three of the five rings of the Pentagon." (Source: Wikipedia)
We have written about:
PoE adapter with leads for LANs. The PoE set N9205 contains two passive devices shown in the picture. They are equipped with RJ-45 and 2.1/5.5mm (power) connectors, and prepared for work with majority of popular WLAN devices...
- archive DWR of Sept. 17, 2007
Direct connection to telephone line and link sharing. Sharing of internet connection provided by xDSL technology (e.g. Neostrada in Poland) is a very popular way of connecting several computers to the Web at home...
- archive DWR of Aug. 27, 2007
Modern SMATV/MATV systems - some tips for designers. Exchange of the main installation equipment in a building requires considerable financial outlays. It is also a challenge for the residents...
- archive DWR of Oct. 1, 2007
Index of published issues.
PoE adapter with leads for LANs. The PoE set N9205 contains two passive devices shown in the picture. They are equipped with RJ-45 and 2.1/5.5mm (power) connectors, and prepared for work with majority of popular WLAN devices...
- archive DWR of Sept. 17, 2007
Direct connection to telephone line and link sharing. Sharing of internet connection provided by xDSL technology (e.g. Neostrada in Poland) is a very popular way of connecting several computers to the Web at home...
- archive DWR of Aug. 27, 2007
Modern SMATV/MATV systems - some tips for designers. Exchange of the main installation equipment in a building requires considerable financial outlays. It is also a challenge for the residents...
- archive DWR of Oct. 1, 2007
Index of published issues.