Network Active Components

Ethernet Switches

In the early days of local networks, the connected devices such as PCs shared an Ethernet cable (coax) over which all data packets ran. Since the length of the cable was limited, two such cables were connected with bridges. These bridges simply reapplied the signal they received on one side to the cable on the other side.

In the course of development, the bridges evolved into switches, which connect each device individually via twisted pair (TP) cables. However, the basic mode of operation has not changed: A switch forwards data packets that it receives at one port to all ports. 

However, a modern switch learns the MAC addresses of the sender and receiver and remembers via which port the corresponding devices are connected to it. Thus, after a short time, it can forward data packets in a targeted manner and only has to use the original method with receivers it does not know. Today's switches perform these tasks so quickly that data packets from different devices are transmitted simultaneously and there is almost no delay. 

Many of the switches available today have additional functions. For example, they can independently recognise the transmit or receive line pairs of a connected cable and adjust to them. This function is described as Auto MDI/MDI-X. Another function is auto-negotiation, with which the switch can negotiate the maximum transmission bandwidth (Ethernet, Fast or Gigabit Ethernet) and also the duplex mode with each connected device.

Many switches can also be configured from a connected PC via a web interface. This allows the administrator to prioritise certain packets (QoS - Quality of Service) or filter addresses, for example.

A special feature are PoE switches which, as "PSE" (Power Supply Equipment), can conduct the supply voltage for the connected device in addition to the data via a twisted pair cable.

Power over Ethernet

The desire to be able to be online everywhere has been growing since before yesterday. The use of tablets, for example, requires - both privately and commercially - ever better and greater "illumination" of buildings or even a site with WLAN. So more and more access points are needed, and these have to be installed in increasingly exposed locations. But what happens if there is no power connection available? And if this can be realised at best with great effort or not at all?

Another scenario comes from the security and surveillance of a building or site. IP cameras must always be placed in locations that are not connected to the power grid.

The solution for these cases is always the same and it is called: Power over Ethernet, or PoE for short. With this technology, power is brought to the place where it is needed via a data line. With current standards, up to 15.4 W (IEEE 802.3af) or even up to 30 W (IEEE 802.3at, often called PoE+) power can be brought to the device to be supplied. 

This is often done via network switches that support PoE, also called PoE switches. 

Alternatively, a PoE injector can be looped in between the switch and the end device, which brings power to the cable to the end device in addition to the data. If several connections are to be supplied with PoE in this way, this can be done via a multi-port injector or PoE midspan.

If the end device cannot use the transmitted power because it is not PoE-capable, a so-called PoE splitter is used, which separates data and power again and brings both to the end device on separate lines.

Take the opportunity to test PoE in practical use. We offer PoE products in ROLINE quality at a good price!

Do you have any further questions about the devices on offer or about other topics relating to Power over Ethernet? Just give us a call, we'll be happy to help you.

Industrial Networking

Industrial switches, media converters, SFP modules, PoE and industrial power supplies are designed for use in the harshest conditions. These hardened industrial solutions operate within an extended temperature range in environments with extreme heat or cold and in areas with high levels of vibration and shock. The industrial solutions also comply with industrial safety standards and provide protection against ESD, EMI and surges.

WLAN standards

Like everything else in the world of technology, WLAN has undergone a long process of development over the last 20 years. The performance, speed and range have been constantly improved. The IEEE (Institute of Electrical and Electronic Engineers) in New York is responsible for this.

Although many people associate the string IEEE with WLAN, the meaning is unclear to many. In 1997, the IEEE established the first standard for wireless connections in radio networks, namely IEEE802.11.

Powerline or dLAN

With powerline technology, it is possible to use the normal power grid for data transmission. This makes it possible to create a network wherever there are power sockets without the need for complex and often expensive LAN cabling. Alternative names for powerline technology are PowerLAN, PLC (powerline communication) and dLAN (direct LAN). Powerline adapters are available with LAN connections and WLAN, which makes it possible to supply all desired end devices such as PCs, tablets, smartphones, game consoles or smart TVs with Internet at any location in the house.

NAS - Network Attached Storage

A Network Attached Storage, or NAS, is a smart storage device on your home or office network. On the NAS you can store all the files of your family or colleagues, from important documents to valuable photo, music and video collections. You can access the files via a web browser or mobile apps and use various services, such as audio. And video streaming, of the NAS via the Internet. Recording of your video surveillance can also be done through the NAS. Backup with and to cloud services such as Dropbox or AMAZON are also possible. Share content, also via the Internet, with definable users.