What is a powerline adapter?

Powerline is the English term for the power cable. A Powerline adapter So called because it uses the power line for data transmission, such as Internet access. The adapter feeds data from the local network into the power grid so that another adapter can filter it out again and feed it into another Ethernet cable or WLAN.

In this way, the adapter enables networking within an apartment or house without laying cables from one room to another. It is therefore an alternative, but also a supplement to WLAN, which also provides a wireless data connection.

Powerline adapters are usually housed in a connector housing and are therefore particularly easy to use. Some of them are also designed as adapter plugs so that they don't even block a socket.

The best powerline adapters

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When do you need a powerline adapter?

The Powerline adapter allows computers to be networked inside buildings where the laying of network cables is not permitted or desired.

It therefore initially offers a functionality similar to that of a WLAN router. However, both types of local networking have specific advantages and disadvantages. Which of the two solutions is more attractive therefore depends on the respective application. The Powerline adapter can be used both for the internal networking of computers in a LAN and for sharing Internet access in different rooms. Another application is the connection to a DSL router for Internet access if the DSL connection does not lead to the room where the Internet is required.

How does a powerline adapter work?

The mains voltage in the usual household alternating current network has an almost sinusoidal curve. A Powerline adapter changes this voltage curve minimally in such a way that these changes can be recognized and read out again by other adapters. This technique is called modulation or demodulation and is often used for data transmission. The word modem is also derived from these terms. From the point of view of the power grid, the powerline signals are tiny disturbances that are within the tolerance ranges and therefore remain harmless. The signals sent out by the powerline adapter as apparent disturbances in the AC voltage can also be easily blocked with commercially available mains filters, such as those found in some socket strips or those offered for DIN rail mounting in the meter box.

How to connect the powerline adapter?

Putting the Powerline Adapter into operation is very easy. After being plugged into a socket, the devices usually try to find additional adapters on their own. In order to prevent unauthorized access to the powerline network, the adapters usually offer a pairing function. The pairing process is triggered either with a button on the adapter or via software from a connected PC.

After enabling the pairing function, the devices negotiate a cryptographic key, which is then used to encrypt all data transmission between the adapters. To prevent someone from eavesdropping on this key exchange at another point in the same power supply system, the Powerline adapters can be plugged into a shared multiple socket with a line filter for pairing.

How many powerline adapters can you use?

The number of powerline adapters that can be used simultaneously in the same data network depends on the firmware of the devices used. It therefore varies from manufacturer to manufacturer and sometimes also from model to model.

A practical, soft limitation of the number also results from the fact that all participants in a Powerline network share the available bandwidth. This means that the more powerline adapters are actively transmitting in the same network, the slower the data speed that each individual user perceives on their computer.

How much that is in individual cases also depends on the adapters used, since the maximum possible data speed tends to increase even with Powerline.

What is the power consumption of powerline adapters?

Powerline adapters generally require very little power and also usually have power-saving functions that reduce power consumption when inactive.

Such adapters switch off automatically after a few minutes, for example, when the Ethernet connection is disconnected, for example when the connected computer is switched off. They turn on again automatically as soon as a signal is present at the interface again, i.e. when the computer starts up.

With a typical Powerline adapter, this reduces the power consumption from around 600 mW to around 85 mW. With continuous operation, i.e. 24 hours of operation every day, the annual consumption adds up to around 5 kWh and with pure standby operation, the power consumption is less than 1 kWh per year.

What are the advantages of powerline adapters?

The powerline adapter offers advantages primarily through the use of existing power lines for the data connection, so that no cables have to be laid between the adapters.

This is one reason for the ease of installing Powerline networks. The connection to the PC is usually easily possible with an Ethernet cable, since the computer needs a power connection anyway. There must therefore be a socket nearby that can also be used for the adapter.

The powerline adapter also has advantages over WLAN. Its signal is not obstructed by walls and can therefore bridge greater distances in buildings. In addition, Powerline is more secure from unauthorized use because physical access to the power grid is required.

What are the disadvantages of powerline adapters?

The disadvantage of the powerline adapter compared to the WLAN is that a connection is only possible within the same power network and the powerline signals are blocked by any network filters that may be present. The use is therefore limited in principle to rooms with a common power connection.

However, this can also be advantageous because it makes unauthorized access to the home or company network more difficult. Furthermore, each adapter occupies its own socket, unless it is designed as an adapter plug and thus provides a power connection for other devices.

If several computers are connected to a powerline adapter with only one Ethernet socket, an Ethernet switch is required. This prevents the adapter from automatically switching off when the connected computer is switched off, unless it is also switched off.

What should you consider when buying a powerline adapter?

Before powerline adapters are purchased for local networking, the availability and number of free sockets at each of the planned computer locations should be checked. If there is a shortage of sockets, adapters that loop through the power connection and therefore do not block any sockets are advantageous. It is also a good idea to determine the number of computers that can each be connected to a common adapter. If this is the case, then the purchase of Powerline adapters with several Ethernet interfaces should be considered. On the one hand, these can reduce installation and operating costs, since the number of Powerline adapters required is reduced. On the other hand, the automatic switch-off of the adapter remains functional when several computers are directly connected, in contrast to the use of an Ethernet switch.

Cover photo Source: Amazon.de