Last updated: August 12, 2021

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Welcome to our big DSL modem test 2021. Here we present all the DSL modems we have tested in detail. We have compiled detailed background information and added a summary of customer reviews on the web.

We would like to make your purchase decision easier and help you find the best DSL modem for you.

You will also find answers to frequently asked questions in our guide. If available, we also offer you interesting test videos. Furthermore, you will also find some important information on this page that you should definitely pay attention to if you want to buy a DSL modem.




Summary

  • DSL modems connect you to the Internet. Technically, they must be compatible with the type of DSL connection you have.
  • A modem is available as a "standalone", i.e. a pure modem without many functions, and as a modem router, i.e. a WLAN router that includes a modem function. Routers support various standards and come with a variety of extras.
  • In addition to the pure Internet connection via LAN, a WLAN router also transmits on one or two WLAN frequencies, offers USB interfaces and more LAN connections than a pure modem, as well as Wifi Protected Setup.

The Best DSL Modem: Our Picks

Guide: Questions you should ask yourself before buying a DSL modem

Why do I need a DSL modem and what are its advantages over other ways of going online?

The DSL modem forms a permanent physical and logical connection between your home and the network operator (the exchange), a "dedicated line" so to speak.

Such internet access is more stable than a wireless connection and it guarantees a relatively more reliable bandwidth than other options.

To access the internet from home, a modem is needed that uses one of the technologies explained above. (Image source: 123rf.com / 98149341)

The alternatives to a DSL modem are internet access via TV cable (cable modem technology), data transmission via power cable (powerline communication), broadband access via satellite or mobile access (UMTS, LTE).

Even though cable networks offer a good option for Internet access, a DSL modem is still the better choice for many.

TV cables are not laid everywhere, and these lines are often missing in commercial areas. Telephone lines, on the other hand, are available.

Moreover, only three quarters of households in Germany have TV via cable.

DSL providers operate nationwide, cable network operators regionally, which is why there are no uniform offers.

In addition, TV and radio channels block a large part of the frequency range, leaving not much for internet and telephone.

With DSL, the entire line is only available for telephone and internet.

Internet via power cable also cannot keep up with DSL in terms of bandwidth. 2 MBit/second for 50 to 150 users is common.

A DSL modem is also cheap to buy (more on this later), whereas powerline technology is complicated and expensive and therefore a location-dependent offer.

Although all households have electricity, comparatively few potential customers are reached.

In addition, internet reception via the power cable is disturbed by radiation from radio services and other electrical devices on the power grid.

Via satellite, all users throughout Europe share the same bandwidth, so there is not much data rate left per person during peak hours.

With a DSL modem, you only "fight" for bandwidth with other users in your home.

In addition, a satellite is about 40,000 km away from the earth's surface.

Therefore, there can be strong delays on this long transmission path, which make real-time services (for example Voice-over-IP or Telnet) and online games a game of patience.

DSL also has a more reliable network capacity than mobile telephony.

The utilisation of the networks has increased greatly due to offers and smartphones. In many places there are hardly any free frequencies for UMTS.

LTE has the same problem. More users within a mobile phone cell reduce the transmission rate to up to 2-3 MBit/second.

Radio connections are also more susceptible to interference than those via lines.

What else do I need in addition to a DSL modem?

Depending on the type of connection, the accessories may vary, but basically a DSL splitter or a network termination device (for ISDN) is necessary. However, these are usually supplied by the provider.

There are also modems with built-in splitters that are connected directly to the telephone socket. The splitter is also not necessary with a VoIP telephone connection.

Since a single modem can only connect one computer to the internet, a (WLAN) router is usually added for multiple users.

With a cable modem you almost always need an external router, other types of modems are nowadays already built in as part of other hardware.

This means that a WLAN router itself takes over all tasks: it is a modem, router, WLAN receiver, telephone system and server all in one.

The WLAN access point or WLAN repeater further increases the range of the signal.

Decision: What types of DSL modems are there and which is the right one for you?

If you have a DSL connection set up at home or change providers, a modem is usually supplied by the operator.

Even if you buy a modem yourself - as has been possible for a few months now - the modems do not differ so much that we could give you many tips here.

What you should also think about, however, is the choice of DSL line that your new modem will use.

DSL is not just "DSL" (Digital Subscriber Line). There are seven technologies within the DSL family:

  • ADSL
  • ADSL2+
  • SDSL
  • VDSL2
  • VDSL vectoring

The best known is ADSL, which is primarily offered for private households.

Depending on the factors you attach importance to when buying and the digital infrastructure into which the modem is integrated, ADSL does not always have to be the first choice.

The following section is intended to help you choose the right type of DSL for you. We will therefore briefly introduce each of the technologies and point out their advantages and disadvantages.

What are the advantages and disadvantages of ADSL?

With asymmetric DSL, the download has a higher speed than the upload, hence the name.

This was chosen because it reflects the behaviour of the average internet user.

When surfing the net, downloading is generated, also by downloading files such as pictures, music or programmes. Very little is uploaded to web servers.

ADSL transmits data via copper cable, so the normal telephone line is also used here. If you have fibre optic cables at home, you cannot use asymmetric DSL.

Although telephone and internet use the same cable, you can still make phone calls and go online at the same time.

All you need is a second telephone socket or a DSL splitter provided by your Internet service provider.

The splitter provides different frequencies for the voice and data service.

Advantages
  • Fast download
  • No own line necessary
Disadvantages
  • Slow upload
  • Cannot be used with fibre-optic connection
  • Ideal values unattainable in practice
  • Cannot be used without a nearby exchange

Under ideal conditions, you can achieve a maximum downstream of 8 MBit/second and a maximum upstream of 768 kBit/second with ADSL.

With DSL providers, however, you will hardly reach these figures in practice, as the speeds are "throttled" in order to put less strain on the network.

The usual speeds for private customers are 1-3 MBit/second for the download and between 128 and 512 kBit/second upload speed. You may find occasional offers with 4-5 MBit/second downstream.

For ADSL customers, the distance to the nearest exchange is also important (there, the data is transferred from the copper cables to fibre optic lines).

Ideally, a distance of three to five kilometres cable length (not as the crow flies) is required to achieve an optimal transmission speed.

If you live further away, this speed decreases. Thus, ADSL is not a good choice above a certain distance.

Telekom does not say exactly where the exchanges are located. Presumably they are close to post offices, because Deutsche Post and Telekom were one company until 1995.

What distinguishes ADSL2+ and what are the advantages and disadvantages?

The great success of ADSL led to the further developments ADSL2 and ADSL2+.

In Germany, the switch was made more or less directly to ADSL2+, so we will only discuss the latter in more detail here.

ADSL2+ offers a higher transmission rate, a greater range (at the same rate as ADSL) and less interference.

Problems that used to lead to a loss of connection now only reduce the transmission speed.

Advantages
  • Faster download
  • No dedicated line needed
  • Greater range
  • Less interference
Disadvantages
  • Slow upload
  • Cannot be used with fibre-optic connection
  • Ideal values only unattainable with short distance
  • Close exchange is important

Up to a line length of about 1.5 kilometres, ADSL2+ achieves 25 MBit/second.

The fact that you as a customer are often only presented with 16 MBit/second is due to the fact that Deutsche Telekom has decided on this restriction. However, the lines would be able to cope with the full load.

So if you want it to be fast, you have the option of looking for an Internet provider that offers telephony via VoIP and does not otherwise offer POTS and ISDN.

But again, if you are far away from the exchange, this won't help either. In addition to the 25 MBit/second download, there is up to 3.5 MBit/second upstream.

What distinguishes SDSL and what are the advantages and disadvantages?

This technology is the opposite of ADSL and its variants in two important ways.

SDSL access is offered at a higher price, but this technology scores above all with a fast upload. This makes it attractive for business customers.

Advantages
  • Faster upload
  • No own line necessary
  • Good for long distances
Disadvantages
  • Slower download
  • Ideal values difficult to reach
  • More expensive offers

Especially in the office, central servers are often used for digital documents. Another example that generates a lot of upstream is video conferencing.

On average, downstream and upload share the data rate 50:50, hence the name Symmetric DSL.

Expressed in figures: at least 144 kbit/second, but usually between 1.5 and 2.3 MBit/second are available for up and down each.

In addition, SDSL copes better with longer lines than other technologies.

What distinguishes VDSL2 and what are the advantages and disadvantages?

Two standards have developed for VDSL, VDSL1 and VDSL2. However, only the latter has prevailed, which is why "VDSL" is generally used as a term for VDSL2.

This transmission technology has one major difference from the other two: it uses a mixture of copper and fibre optic cables.

The further the optical fibre reaches the customer, the higher the speeds possible.

Advantages
  • Fast download
  • Uses hybrid line system
  • Prefer connection possible
  • Triple Play
Disadvantages
  • Slow upload
  • Copper cable must be as short as possible
  • Ideal values difficult to achieve

VDSL2 (Very High Speed DSL) is compatible with all ADSL variants, which is why it can be offered relatively easily as a successor to ADSL.

Around 50 MBit/second download speed is common in Germany. How high the transmission speed is depends greatly on the length and quality of the copper cable that connects the fibre-optic part of the network to the DSL modem at home.

VDSL makes it possible to prioritise one data connection over another and it enables "triple play", i.e. offering television, internet and telephone together.

What distinguishes VDSL vectoring and what are the advantages and disadvantages?

This technology was further developed from VDSL2 and brings you even higher transmission speeds on your internet connection: around 100 MBit/second downstream.

However, since the technology requires a few special features, the existing telephone connection may have to be converted.

A fibre-optic cable from the exchange to the last few metres to your flat is a prerequisite; a copper cable is only allowed at the very end.

There must be a DSLAM (a type of DSL distributor) between the exchange and the subscriber connections of you and your neighbours.

All copper lines that lead to the individual connections come from this.

Advantages
  • Fastest download
  • Fastest upload
Disadvantages
  • Copper cable must be even shorter
  • Home connection perhaps not yet converted
  • Ideal values only possible with very short distance
  • DSLAM prerequisite

In 2015, it was decided in Germany to upgrade the fixed network lines to VDSL vectoring.

It is therefore possible that the telephone connection at your home has already been changed; you must ask your network operator about this.

According to Deutsche Telekom, up to 80 percent of households will have broadband internet access in 2018.

Purchase criteria: You can compare and evaluate DSL modems based on these factors

In the following, we would like to show you which parameters you can use to compare and evaluate modems.

This will make it easier for you to decide whether a certain device is suitable for you or not.

In summary, these are:

  • Weight
  • Dimensions
  • WLAN standard and its frequencies
  • LAN connections
  • USB connections
  • WPS
  • Colour

In the following paragraphs you can read about the individual purchase criteria and how you can classify them.

Weight

This factor may be important when it comes to shipping, the price of which depends on weight.

Otherwise, a router that is a little heavier will stand or lie more securely than a very light device.

A light modem might be interesting if it has to be transported often (for example, if you move house frequently).

Going through all the criteria can be a lot of work. In the end, however, you will have a product with which you are completely satisfied.

Dimensions

Most modems are not very different in size, but if you are short of space under a table or in the corner of a room, you can of course deliberately look for devices that are as small as possible.

The dimensions are not a criterion for performance, but the space for interfaces of all kinds could be limited with very small modems.

WLAN standards and their frequencies

Since standards have been developed almost continuously since 1997, there are now many different names.

We explain here what the abbreviations mean and what is the important factor for you regarding WLAN standards.

Even though the technical differences between the standards lie in the channel width and modulation, the only thing that is interesting for you as a user is the maximum possible transmission rate.

The "IEEE 802" project is generally concerned with standards for local networks.

IEEE is the Institute of Electrical and Electronics Engineers. The number 802 was chosen because it all began in February 1980.

In total, the 802.11 family consists of 12 standards, but most of them have already been discontinued or are still far from being ready for discussion.

Therefore, we will only deal here with the "milestones" of the standard development that are also applied to the current modems.

802.11 was introduced in 1997 and uses a frequency range of 2.4 gigahertz (GHz). A maximum of 1 MBit is transmitted per second, so this standard has long been outdated.

802.11a and 802.11b were developed from it. Compared to 802.11, standard b still manages 11 MBit/second.

802.11a operates in the 5 GHz range and transmits an impressive 54 MBit/second. Another advantage of the 5 GHz frequency range is that it is less susceptible to interference than 2.4 GHz.

So if the modem of your choice is capable of transmitting on 5 GHz, you should prefer this range.

The next developed standard is called 802.11g. It also achieves 54 MBit/second, but uses the 2.4 GHz range.

The best known and often used is 802.11n. This standard supports 2.4 and 5 GHz and has a maximum data rate of 600 MBit/second. In 2018, this standard was renamed Wi-Fi 4 by the Wi-Fi Alliance.

802.11acis only a few years old. Theoretical 1300 MBit/second sound fantastic, but are probably not achievable in practice.

Also, there are not so many suitable routers here yet. In 2018, this standard was renamed Wi-Fi 5 by the Wi-Fi Alliance.

A look into the future: the 802.11 standard should be usable this year. To improve the quality of transmission, a new frequency range is being targeted: 60 GHz.

No devices are yet transmitting in this range at all. In 2018, this standard was renamed Wi-Fi 6 by the Wi-Fi Alliance.

Transmission rates of all types of DSL presented

Keep in mind that the rates are ideal values and guidelines and unfortunately cannot be guaranteed. However, they are sufficient for a rough comparison.

DSL variant Transmission Download (MBit/second) Upload (MBit/second) Range in km
ADSL Asymmetrical 8 0.786 Approx. 5
ADSL2+ Asymmetrical 25 3.5 Approx. 1.5
SDSL Symmetrical 2.3 up to 8 Approx. 2
VDSL2 Asymmetrical 50 10 Approx. 3
VDSL-Vectoring Asymmetrical 100 40 Approx. 0.4

LAN connections

In some cases, you may want to connect your terminal devices to the modem via LAN cable instead of via WLAN.

If you prefer a more secure connection or if the PC does not have a WLAN-capable network card, the only alternative is to use a LAN cable.

Most routers have several LAN ports and even though WLAN is becoming more and more important these days, at least one cable connection to the modem is a prerequisite.

This is usually also used when setting up the WLAN network at the beginning in order to be able to call up the router's user interface on the PC.

USB ports

Most modern routers have one or more ports for USB (2.0 or 3.0).

By connecting directly to a USB stick or an external hard drive, the modem thus becomes a network storage device.

This is an advantage if several devices are used in the home network and you have to search laboriously to find out on which device a file you are looking for is stored.

Many of these devices can play multimedia files. To prevent chaos, you can store such files centrally on the router.

A modem on which this is possible has a "NAS" function (Network Attached Storage). The device thus becomes a "media server" and, as mentioned above, can easily recognise sticks or hard disks.

You have to find out exactly what the settings are for this online or in the user manual of your DSL router.

WPS

The Wifi-Protected Setup makes it possible to integrate additional devices into the WLAN home network very easily.

The tedious setting via user interfaces and the entry of IDs and complex passwords is no longer necessary.

Routers from the 820.11n standard onwards all have this function. WPS can be used via "buttons" or PIN.

With variant one, a button is pressed as simultaneously as possible or at very short intervals both on the WLAN router and on the device that is to be connected.

The access point then simply transmits the access data to the other device. Short spatial distance and possibly several attempts are necessary.

With the PIN method, an eight-digit sequence of numbers is entered in the router's user interface.

It can be specified either by the end device (secure) or by the router (insecure). The router's number sequence can usually be found on the bottom of the device.

Colour

This is of course a very subjective criterion and may not play any role at all in choosing the right modem.

However, there is also the possibility that there are no or only minimal differences between two routers in terms of specifications.

If these two devices have different colours, you are free to decide according to your taste.

Trivia: Interesting facts about DSL modems

What typical problems can occur and how do I solve them?

As always, when technology is involved, it can happen that even though everything seems to be set up correctly at first glance, you can't get an Internet connection.

Here we have summarised the most important steps that can help you with troubleshooting.

The first thing to look at is the DSL router (modem). What do the indicator lights look like?

A permanent glow or flickering generally indicates that the device is synchronised with the exchange and that there is no error here.

A flashing light indicates that synchronisation is in progress. There is only a problem if the light flashes for a longer period of time.

Then something is wrong either with the modem settings or with the Internet provider.

You can check the configuration of your own router again with the help of the user manual.

If there is no error, the only thing left to do is to call your DSL provider. If that doesn't yield anything, the problem may be in the cabling.

Since current devices are modems, routers and splitters in one, the router only has to be connected directly to the telephone socket.

However, it is important to choose the right side. F-coding is reserved for telephones, N-coding therefore for other devices such as modems.

Now check whether the LEDs on the connections (ports) light up or flash if the cables are plugged into the correct port and are seated correctly (if present, also all to the computers).

Normally, the lights on your DSL modem are on. If they flash or do not light up at all, the fault may lie with the device or the cable. (Picture source: 123rf.com / 87816536)

If nothing lights up, you can first test other cables to see if the cable is broken. If this does not change anything, the fault is probably with the device.

If you haven't found the error yet, it's time to check the network settings.

If the PC is connected to the modem, you can open a browser and access the user interface of the device.

Under "WAN" or "Internet" (see the user manual for the exact location), enter the preset access data from your operator.

Now check whether the IP settings are correct. Usually the IP address is obtained automatically from the router via DHCP.

For devices connected via WLAN, you can check the SSID and password; these must of course match the data on the router.

Often WLAN can be activated and deactivated in the user interface of the modem or via a switch on the device.

Do I have to or can I switch off the DSL modem at night?

Switching it off or leaving it on continuously has no effect on the quality of the Internet connection, as some users assume.

However, if the device gets slightly warm, it does not hurt to let it cool down overnight.

Normally, the router synchronises itself within a few minutes the next time it is switched on.

In addition, you can also save electricity. For one night it is not important, but 365 times the wattage will add up.

You can find out how high the power consumption really is by looking at the data sheet that comes with the router or an independent device test that you can find online.

According to the German Energy Agency, this can be as much as 20 euros per year. If the modem does not have its own switch, a power strip with a switch is also sufficient.

Whether switching off and thus saving electricity is possible and makes sense depends, of course, on the cabling.

If your (landline) telephone is connected to the router and you want to be reachable at night, the router must remain switched on.

Switching off the modem when it is not in use also has a security benefit. (Picture source: 123rf.com / 79634019)

Every active Internet connection can potentially be hacked, and if the WLAN password is insecure, others could "hook in" with their devices and thus increase your data consumption and also reduce the bandwidth

Can a DSL modem have a virus?

That is possible. In the worst case, security gaps in devices from different manufacturers make it very easy for hackers to penetrate the private network and cause damage.

If the telephone is also connected, expensive calls could be made via your connection.

Hackers can also infiltrate deceptively real-looking phishing pages. If you then log into online banking via these pages, the hackers also know your access data.

Less bad, but very annoying, can also be when spam mails are sent via your router.

An infected modem can also mean that files on network computers are no longer protected.

Simple points to increase security are:

Check that the router has the latest firmware. Usually, when there are changes or known security holes, the companies automatically deliver updates.

You can check in the user interface whether your device automatically checks for updates.

Or you can start the search yourself at regular intervals. Older devices should be replaced if a vulnerability is made public and there are no more updates from the manufacturer.

If it is not absolutely necessary, switch off the WPS pin. This setting allows new devices to be integrated into the wireless network by entering a PIN or pressing a button.

However, it can happen that this function has not been correctly installed and thus forms a point of attack on the router.

Ideally, a firmware update will solve the problem. If this does not work, you should deactivate the WPS PIN in the user interface.

Depending on the router, it is possible to deactivate only the PIN or you have to deactivate WPS in general.

Otherwise, you can always change your network password and make it more secure.

Because even with WPA2, which is basically a secure system, it depends on what you choose as a password.

Choosing your own password and not continuing to use the preset password is a prerequisite.

The longer and more complex the new password, the better. At least 20 characters including numbers and special characters are recommended.

If you are unsure, test your numerical sequence on a trustworthy website on the subject of "measuring password strength".

In addition, there is also the possibility of checking whether your data is being redirected (keyword: phishing sites).

You can always do a quick check to see which DNS server your PC's request is going to.

Open the command prompt on your computer and enter "ipconfig/all". The IP address of your router should then appear under "DNS server".

Then check in the user interface of the router which DNS server is entered there.

You can then test the IP address that appears there online in an Internet database. This should then show your Internet provider as the owner of the IP.

The router's user interface can also be used to display all devices in the home network. This list should only contain devices that are known to you.

The router protocol can also be viewed there. In this way, you can find out whether changes were made in the menu or from where the user interface was called up.

In addition, logins to the WLAN are noted, so you can see if someone tried to break in from the outside.

Can I use my DSL modem abroad?

Even if this is possible in some cases, you should not assume that it is.

Many manufacturers use their own ADSL line codes, so it is likely that your DSL modem will not be compatible with the local standard abroad. In such a case, it is advisable to consult a local expert.

It may be possible to adapt your device to the local standard.

What is xDSL all about?

You may come across this term online more often. It is used as a "generic term" for all DSL variants, with the "x" serving as a placeholder for A, S, V and so on.

When "xDSL" is mentioned, it does not refer to a separate technology.

Picture source: 123rf.com / 12338508

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