Unfortunately, it is not as easy as just buying a second router and plugging it into one of the currently unused TAE -Sockets, there can be only one DSL-Router in your home (that is unless you want to pay for a second line).

You say you need a lot of internet on the second floor but, it is unclear if you also need internet on the first floor. If internet is needed on the second floor ONLY, then the solution might be to simply move the existing router to the second floor. If you are lucky, it might even be enough to just plug the router into one of the TAE -Sockets on the second floor. If less lucky, rewiring of the sockets may be necessary.

Things become tricky if you need internet on BOTH floors. You will need a WIFI access point on the second floor that connects to your DSL router. Devices (smartphones, tablets, laptops etc.) on the second floor will connect to the router through this new access point when on the second floor and to the router directly when on the first floor. The tricky part is the backhaul connection between the router and the additional access point. I see three options to establish that connection:

Option a, WIFI accesspoint via Ethernet:

The most reliable solution will be a direct connection via Cat. 5e (or better) Ethernet wiring. This can be a realistic option if the existing telephone wiring between the TAE -Sockets happens to be layed in conduit. In this case, an electrician may be able to pull out the phone wire and replace it with Ethernet wiring without too much hassle and cost. TAE -Sockets are replaced with Ethernet sockets inthe process.

If there is no usable conduit between floors, then Ethernet wiring is unlikely to be an option, as installing it requires drilling through the floor/ceiling and maybe even slotting the walls, plasterwork and new wallpaper if you want a hidden installation. Should you be renting, you'll need the agreement of your landlord to any installation of new wiring.

Option b, WIFI repeater:

A simpler solution is a WIFI repeater. This device will create a wireless connection to the router and re-distribute the wifi connection on the second floor. The difficulty here is to find a spot for the repeater where it can establish a reliable WIFI connection to the router and, at the same time, be reliably accessible by the client devices. Feasibility of this solution depends heavily on your building and situation. E.g., if the WIFI spectrum is filled by many other WIFI networks (as you would expect it in densely populated areas) then it can be difficult to get a reliable connection.

Optoin c, Power-line communication:

The third option is be similar to option a, but the backhaul connection between the router and the accesspoint requires no new wiring. Instead, the signal is transported over the existing mains power cables. You'll need two devices, one is plugged into a mains socket near the router, the other is goes into a mains socket at a suitable spot on the second floor. The device on the second floor will again act as a WIFI access point and communicate with the power-line device near the router. That device in turn connects to the router via a short Ethernet patch cable.

Unfortunately, power-line can interfere with the DSL connection, sometimes to a point where internet access becomes impossible. This is true in particular if you have a fast VDSL Vectoring line ("Magenta Zuhause" "M" or "L") .

To recommed a solution, some information is required:

- What kind of building do you live in? Concrete floors for example are bad for the wifi repeater solution.

- What type of DSL connection are you using, what did you buy from Deutsche Telekom?

- Do you use TV over IP ("Telekom EntertainTV")? This services has special requirements to the network and needs careful selection of both WIFI repeaters and power-line devices.

Hello !

In order to usw WIFI across serveral levels the best practice is using Access Points.

Access Points are connected via the LAN interface of the router and provide WiFi across the Building.

Therefore you need a power socket, a LAN cable (patch cable) and an Access Point.

Using a repeater can help you to improve your WiFi within a smaller area oder througout the same level of the Building. You might build up a mesh network with 2 or more repeaters, but therefore a Router and repeaters are required which support Mesh.

Some router models can be set up to work in Access-Point Mode oder Repeater Mode, but they also need to be connected via LAN with the main router.

Greetings