Frequently asked questions about dLAN
Questions:


General


Applications

dLAN generally


dLAN Highspeed


dLAN duo


Security


Technics


dLAN Highspeed


dLAN duo





Answers:
Here we hope you will find all the answers to your dLAN questions.



Question:
What is dLAN?

Answer:
dLAN means "direct LAN", i. e. "directly networked".

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Question:
Does dLAN stand for Internet via power supply?

Answer:
Yes and No! You can install your network so that you can use your ADSL access on all power sockets. However, Internet comes into your building separately via a separate ADSL modem.

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Question:
Are dLAN products compatible to HomePlug devices of other manufacturers?

Answer:
To obtain optimum performance and usability we recommend you use devolo products. They are tested and proven for interoperability.

Furthermore, devolo dLAN devices are compatible with the HomePlug standard, i. e. they operate with all other devices compatible with this standard.

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Question:
Do I have to modify the power supply to install the dLAN adapters? Do I encounter 230 volts?

Answer:
No, you don't have to modify anything on your power supply lines. And you do not encounter 230 volts.

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Question:
Do I have to turn off the fuse to install the dLAN adapters?

Answer:
No, you don't have to.

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Question:
In my house are three separate phases. Can dLAN connect one phase to another?

Answer:
Yes, it can.Phase coupling operates without the installation of a phase coupler using dLAN adapters. You also can establish your network connections via two or three phases.

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Question:
I'm living in a very old house with old power supply lines (some without separate earth-ground connection). Will dLAN operate nevertheless?

Answer:
dLAN will also operate correctly in this case.

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Question:
Can my neighbour tap into my data when he is connected with the same power supply?

Answer:
devolo urges you to use the internal device DESpro Encryption! Entering a password which differs from the factory default will activate the encryption and will protect your network.

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Question:
How safe are my data? Is it possible to tap into them in some way?

Answer:
We urge you to use the internal device encryption! Entering a password which differs from the factory default will activate the encryption.

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Question:
Do I have to plug the devolo dLAN adapter directly into the wall socket or can I also plug it into an extension or into a multiple socket (some with separate switch)?

Answer:
Short answer: You can. Both.

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Question:
My computer has a crowbar circuit. Can I use the dLAN devices with a crowbar circuit?

Answer:
Please plug in the dLAN adapter before the crowbar circuit, because dLAN devices will either not operate with conventional crowbar circuits or can lose performance and stability. One exception is the crowbar circuit MNT-POWERLINE from Phoenix. You can purchase it under: www.akkukompass.de.

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Question:
Which devices do I need for the initial installation of a dLAN network?

Answer:
You will always need a minimum of two adapters for the initial installation. If you wish to connect your network to the Internet, you need at least one adapter with an Ethernet interface. This adapter is to be connected to an ADSL modem (in this case, only one participant of the network can use the Internet) or to an ADSL modem router (allowing all participants of the network to use the Internet at the same time).

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Question:
Are dLAN devices compatible with other LAN products?

Answer:
You can combine devolo dLAN products with all other devolo LAN products or with all devices which conform to the IEEE 802.3 standard.

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Question:
Do I have to worry about electric shocks from the Ethernet?

Answer:
No. The two electric circuits are separated from each other.

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Question:
Do dLAN adapters interfere with other domestic appliances?

Answer:
No, they don't. dLAN products are certified according to all essential standards, and are also EMC tested for emissions and interference.

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Question:
Do other domestic appliances interfere with dLAN devices when they are operating?

Answer:
All devices which are sold within the EU have to be labeled with the CE mark. This guarantees that the devices do not interfere each other.

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Question:
On which frequences does dLAN operate? Does this technology interfere with the reception of radio or amateur radio?

Answer:
Typically, radio broadcasts are transmitted on UKW in the range of 87.20 to 108.00 MHz. The frequences used by dLAN-technology are in the range of 4MHz to 21MHz so they cannot interfere with your UKW radio. The technology is based on the HomePlug standard, in which the transmitting level is specially lowered within the amateur radio band. The transmitting level used is very small and with symmetrical coupling, only a small part of this power will be radiated by the power grid. Consequently in the amateur band no interference is expected. .

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Question:
Does dLAN deal with Powerline Internet?

Answer:
No, with Powerline Internet, longer distances had to be covered which could only be realized with higher signal levels. The HomePlug standard applies to indoor data communication and uses only very small signal levels.

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Question:
Is there a risk that electromagnetic interferences will be distributed throughout the house using dLAN adapters? Or even to the neighbours?

Answer:
dLAN devices are tested according to the same standards as all other electric devices (EN55022), and are allowed to generate no more noise than any other electrical equipment. For example, dLAN devices will produce no more interference than your power drill, e.g.

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Question:
When were dLAN products first available?

Answer:
The dLAN products have been available since April 2003.

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Question:
Do any costs arise when adding more users?

Answer:
No, the only costs arise by purchasing the necessary number of dLAN adapters. This technology is not the technology "PowerLine Internet" which realizes Internet access via your electricity supplier. dLAN devices only enable the connection of several computers to an indoor network — without installing additional cables. These devices comply with the so-called HomePlug standard. However, when you connect your internet modem router to a power socket, all your network computers can connect to the Internet.

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Question:
Is it possible simply to add more users on the power lines or is there something to consider on the part of the energy provider? Can the provider collect charges?

Answer:
It's easy. The provider does nothing and can't collect any charges.

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Question:
Do I need a particular provider for Internet access or a specified dial-up procedure? Or can I keep up my present dial-up mode?

Answer:
Any provider is suitable, and the Internet dial-up is absolutely independent of using dLAN devices. You also can network your computers via the dLAN products without Internet access. If you then wish to add the internet to your network you will need a router.

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Question:
The power supply operates with 50Hz. Is it possible to achieve reasonable ping times in the range of milliseconds?

Answer:
dLAN doesn't operate with a 50Hz alternating frequency. dLAN operates in the range of MHz. Therefore, ping times in the range of msec are possible.

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Question:
How many dLAN adapters can operate within a one-family house?

Answer:
253 connections are theoretically possible. But in practice, no more than ten devices should transfer data at the same time.

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Question:
If one dLAN adapter is connected to a Switch, is it possible that all other computers connected to the switch can communicate with all other dLAN members?

Answer:
Yes, of course, you can.

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Question:
How can I prevent (e.g. in a flat-sharing community) that someone buys a dLAN adapter and taps into the data transmitted between my dLAN adapters?

Answer:
By using the internal device encryption which will be activated by the enclosed software.

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Question:
Can I combine some dLAN adapters to a private group and have them use a common password?

Answer:
Yes, of course, this is possible.

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Question:
Does configuration software exist configuring dLAN adapters in common?

Answer:
Yes, such software exists.

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Question:
How does the HomePlug technology differ from the Internet Powerline technology? Why did Internet Powerline not become accepted in the market when HomePlug is growing rapidly? Is it another technology?

Answer:
There are two important differences between these two technologies HomePlug and Internet Powerline.
With HomePlug the distances which must be covered are smaller, so Internet Powerline had to transmit with much stronger signal levels. This caused different problems, e.g. problems concerning radiation and compatibility to other devices (electromagnetic compatibility CE/EMC).

Furthermore, with Internet Powerline the provided bandwidth had to be shared with up to several hundred members and with Homeplug, the bandwidth is only shared by rarely more than 10.

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Question:
On which level do the dLAN adapters transmit?

Answer:
The transmitting power spectrum is -50dBm/Hz, on amateur radio frequences -80dbm/Hz, with a bandwidth of about 17MHz at about +22dBm (160mW) or about -8dBm (160µW) (all values based on 50 Ohm.) As the coupling is symmetrical, only a small part of this performance is radiated.

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Question:
How much is the power consumption (in watts) of both dLAN adapters from 230 volt power supply?

Answer:
The power consumption of dLAN is between 3 and 4 watts on a 230 volt power supply system.

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Question:
Is the DESpro Encryption really secure?

Answer:
Yes, it is! The DESpro Encryption of the dLAN devices protects your network against unintentional access. Two different attacks are possible,both of which are prevented with DESpro Encryption. To find a suitable key for decoding by a Brute-Force-Attack implies that all existing letters and numbers are being tested one after the other within the chip. The diversity of keys, combined with a transmission rate of data flow between computer and chip which is 100 Mbit/s (Ethernet-Interference), means that after 4500 years on average, a Brute-Force-Attack may succeed. Electronic eavesdropping of code-converted raw-data is another manner of attack. To obtain the original raw data may enable drawing conclusions from the code-converted raw data, but dLAN technology doesn’t allow eavesdropping of converted raw data on your powerline because the chip doesn’t forward directly any code-converted data to the powerline-interface. Within the chip the data-signal will be code-converted and modulated as well. Any offender will only be able to access to the modulated data and that will not help him/her because there is no possibility to revise the modulation.

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Question:
What about compatability of dLAN adapters with operating systems?

Answer:
The configuration software to assign the password, operates with the operating systems Windows 98, Me, 2000, XP, Linux and Mac OS-X. Regarding to the dLAN adapters with USB interface drivers for Windows 98, ME, 2000, XP and Linux are supplied e.g. these adapters only work with these operating systems.

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Question:
I got the impression that the transmission rates, which are indicated by the devolo Informer, are uncommonly low. Which values are normal and realistic? What can I do to boost the transmission rates?

Answer:
Under normal circumstances, transmission rates of 5-8 mbit/s are not uncommon. Please remember that the transmission rate falls with increasing reach (max. 200 m) and the number of adapters (practically not more than 10-15). To increase the data rate you should plug the dLAN adapters directly into the wall socket. Don’t use unnecessary extension cables and multiple sockets. If this cannot be avoided, please make sure that the multiple sockets do not have a crowbar circuit. This could impair or even inhibit the data transmission. Plug in as few devices as possible into the multiple socket. If the data transmission proceeds on one phase instead of two phases beyond, you can expect increased reach and data rate. If it’s not possible to increase the data rates with these options, only the application of a phase coupler could be helpful.

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Question:
How much is the transmitting power of a dLAN adapter compared to cordless home telephone?

Answer:

DLAN

SAR (specific absorption rate; unit: W/kg) is a physical item to measure the absorption of electromagnetic fields in biological material. This absorption causes a warming of the material. It strongly depends on the frequency and on the size of the absorbing item due to resonance effects.

As the size of the absorbing human is nearly constant the SAR is depending most on frequency. As shown in the diagram, the HomePlug technology of the dLAN adapters is—compared to the technology of cellular phones and WLAN—in a frequency band 100-times lower and therefore causes a considerably lower SAR.

Using the in-house p RF noise is on our power lines and how much of it is due to the HomePlug technology? The HomePlug technology emits only a very small part of the signal. To limit the radiation of lines used by telecommunications institutions (including HomePlug), the RegTP lays down the provision 30 (NB 30) which came into effect at 1 July, 2001. It defines the use of frequencies between 9 kHz and 30 MHz (at 1 July, 2003 up to 3 GHz) within and along conductors as well as maximum disturbance level. The limit value of the disturbance levels have to be measured with a required measurement setup at a distance of three meters. See the following diagram:

DLAN
However, a look at the maximum allowable emitted disturbance (according to NB30) of HomePlug shows that this disturbance is very low—compared to the allowed limits (according to ICNIRP recommandations) of "normal" transmitters in most countries.

This diagram shows the maximum electrical field strength according to the ICNIRP directives (in blue) and the maximum values according to the provision NB 30 (in green) applied for a distance of 3m.

In comparison to the "Salzburger Vorsorgewert" of 1000 µW/m², the HomePlug maximum value in a distance of 1 cm nearly underlies by a factor of 4000. An electrical field strength of 0.01 V/m equates to a power density of 0.26 µW/m². A DECT station (cordless home phone) produces a power density of 17500 µW/m² in a distance of 1.5 which exceeds the value of the HomePlug technology by 67,000-times. Even a GSM access point produces at a distance of 50 m a power density which is 60,000-times higher than the power density of the dLAN adapter. Therefore, the risk of biological or health effects by HomePlug or dLAN can be classified as very low.

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Question:
In order to increase the distance of my dLAN-Network I am looking for a dLAN repeater. Does devolo offer such product?

Answer:
You can increase the distance, by combining two dLAN networks with two different dLAN passwords. The repeater is built up by two standard dLAN Ethernet adapters, which you simply connect via an Ethernet RJ45 cable. Please note that physically you are still using one medium, this means the bandwith will be shared between both networks. You can repeat this procedure several times.

DLAN Repeater 

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Question:
Why do dLAN devices reach higher data transmission rates and range than HomePlug products of other manufacturers, even they use the same HomePlug chip?

Answer:
Because of our long lasting expert knowledge in designing analogue circuits, devolo has improved and optimized the analogue circuitry. So devolo engineers adapted optimally the so called AFE (analogue front end) to conditions in European installations. Due to these improvements on physical layer, both the range and the data transmission rates could be increased.

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Question:
Is it possible to establish a connection between a DSL Fritzcard and the splitter via dLAN?

Answer:
Unfortunately no. The line between Fritzcard (DSL modem) and splitter is based physically on DSL technology, whereas the dLAN adapters are physically based on Ethernet technology.

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Question:
Is the technology of dLAN Highspeed downward compatible with HomePlug 1.0 and can Highspeed adapters and HomePlug (14 mbps) adapters be used together in one network respectivly?

Answer:
Yes!

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Question:
Can high resolution videos be transmitted via the dLAN Highspeed adapters?

Answer:
Yes, with complete DVD quality.

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Question:
Does the technology support multicast video server streams (IP-TV / TVoDSL)?

Answer:
Yes.

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Question:
Can devolo dLAN HS adpaters do "Triple-Play"?

Answer:
Yes.

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Question:
Where is the highspeed technology in comparison to the standard Ethernet wiring?

Answer:
100 mbps Fast Ethernet and dLAN Highspeed play in the same league.

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Question:
Why is dLAN Highspeed faster than HomePlug 1.0?

Answer:
The dLAN HS technology exploits the transmission line more effective because of sophisticated and better adapted modulation methods, without changing basic mechanisms of the signal transmission and the media access. Because of this, the downward compatibility to HomePlug 1.0 is ensured.

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Question:
Will the maximum range increase because of the higher bandwidth?

Answer:
No!

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Question:
What does "Triple-Play" mean?

Answer:
"Triple-Play" means the characteristic of data communication products to satisfy the different demands of data, voice (VoIP) and video (IP-TV) transmission comparably.

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Question:
Can an Ethernet interface and a USB interface be used simultaneously?
What will happen if I connect both interfaces simultaneously anyhow?

Answer:
No, the interfaces can only be used alternately. The USB interface will get priority.

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Question:
Can I connect e.g. a remote USB printer with two dLAN duo or dLAN USB adapters via the existing power supply system to my computer?

Answer:
No, the USB interface of all dLAN devices can only be used with the Computer.

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Question:
How does the power save mode operate?
How much economy is realized in the power save mode?

Answer:
The dLAN duo will switch off partially, if it doesn‘t identify any USB voltage or Ethernet Link, e.g. if the Computer is switched off. The devices need approx. 30% less power in power save mode.

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Question:
Which advantage is there when the device in USB mode isn‘t bus powered by the computer?

Answer:
Only a USB bus is able to provide his connected devices (max. 127) with max. 500 mA power supply in common. If the power consumption of the connected USB devices is nearly 500 mA, every additional USB device on the bus will overcharge it.

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Question:
I have a basic ADSL USB modem and want to share my Internet access with a 2nd computer – can I still use dLAN adapters with this setup?

Answer:
Yes – However you will need to configure ICS (Internet Connection Sharing) on the computer that is attached to the ADSL USB modem in order for the 2nd computer to access the Internet. Both computers will need a dLAN adapter connected – and then they can both access the Internet independently. (Please note that the computer attached to the ADSL USB modem will always need to be ‘on’ in order for the 2nd computer to access the Internet). Otherwise, if you have several computers to network, you may also wish to consider upgrading/replacing your ADSL USB modem with a combined modem/router with 4-port hub which can provide a more effective networking solution (this also means that the 1st computer does not have to be on all the time). In this setup, your 1st computer can connect directly to the router via Ethernet, and the devolo dLAN adapters are respectively connected to another spare Ethernet port on the router… and to your 2nd computer.

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Question:
What are the consequences of mixing HomePlug 1.0 dLAN adapters (14 Mbps) with dLAN Highspeed adapters (85 Mbps)?

Answer:
In a mixed network configuration, the adapters will communicate with the highest possible speed, i.e. max. 14 Mbps for standard/Highspeed adapter communication and max 85 Mbps for Highspeed/Highspeed adapter communication.

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