HowTo: FritzBox – Use your own computer via “Linphone” as a VoIP phone-client

If you belong to one of the numerous owners of a FritzBox, you can set up another telephone extension on your computer with a few tricks. That means you will be informed about calls on your Fritz box on the computer and you can also accept this. If you have your microphone and speakers connected, then you can also make calls via the computer.

Hints for our lovely english readers: Basically, many of the articles on are translations from the original german articles. Therefore, it may happen here and there that some illustrations are not available in english and that some translations are weird/strange/full of mistakes or generally totaly wrong. So if you find some obvious (or also not obvious) mistakes don't hesitate to leave us a hint about that in the comment section. 
Also please don't get confused, that instead of a "dot" often a "comma" is used as decimal separator. 🙂

Safety instructions

I know the following hints are always a bit annoying and seem unnecessary. But unfortunately, many people who knew it "better" from carelessness lost their eyes, fingers or other things or hurt themselves. In comparison, a loss of data is almost not worth mentioning, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Even the coolest project is worth no injury or other annoyance.

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Before you start with this article your FritzBox should already be set up and available.

Required tools:

Required material:

In the following list you will find all the parts you need to implement this article.

Create SIP account for the FritzBox

So that you can set up another telephone extension to the FritzBox, you must first create another SIP account. This allows you to log in with the associated login data to your FritzBox.

Log in with your – already known – login data into the configuration interface of your FritzBox.
Once there, you click on “Telefone” …
…and “Telefoniegeräte”.
In the menu that opens, you finally click on “Neues Gerät einrichten” to start the wizard for creating a new SIP account.
From now on, you will be guided step-by-step through the various setting options. In the first window, select which type of phone you want to log on. For a SIP account you select here “Telefon (mit und ohne Anrufbeantworter)”. To get to the next step, click on “Weiter”.
In the next step, you should set this as a “LAN/WAN(IP-Telefon)”. You can also set the name of the phone. Here you should set a better name than “NameEuresSipTelefons”. 🙂 To get to the next step, click on “Weiter” again.
Then it’s time to set a username and password for the SIP account. Enter a user name under “Benutzername” and a password under “Kennwort”. To get to the next step, click on “Weiter” again.
In this step, you can specify which of your available – ie external – phone numbers an outgoing call with the created SIP account should be. At this point, you must select one of the available numbers. To get to the next step, click on “Weiter” again.
You have to make the same decision again for incoming calls. Because the FritzBox can – and that makes sense in most cases – forward external telephone calls to internally registered telephone extensions. At this point you can set which external incoming calls are forwarded to the SIP account to be created. Again, click on “Weiter” to get to the next step.
That’s it with the settings. As a summary you will now see again all the settings made. Check this one again and if you agree, click on “Übernehmen”.
But before the new SIP account is created, you have to fulfill a small security function. To do this, you dial with a phone already connected to the FritzBox the displayed number. It should only be a “beep” to hear. Thus, you confirm the Fritzbox that you really want to create an account and not someone from the outside (via a potential security hole) wants to get access to your switchboard.
As soon as you hear the “beep” on the phone, the view changes and confirms that the new account has been created. Confirm this by clicking on “OK”.
This puts you back in the list of available telephony devices. Here your newly created SIP account is now listed as another telephony device (here “NameEuresSipTelefons”).

Set up Linphone login on the FritzBox

After you have previously created a SIP account on your FritzBox, it is now on correctly set the software on your computer. To do this you first need the software “Linphone”. These can be downloaded for free at How to download and install your program Downloads/Uploads – How the data comes from the internet and disappears and Install programs – an example described.

After installing and running Linphone, you should see this interface.
So that your Linphone now as a SIP client (ie telephone extension) can log on to the FritzBox, you must first enter the SIP account login data in Linphone. To do this, first click on “Assistant”.
…and on “Use a SIP Account”.
This will get you to an input mask in which you can enter the previously created data of the SIP account.
So enter here the login details of your SIP account. This would look like this with the login data from the example above. If you have entered all the files, just click on “USE” …
… and you will be redirected back to Linphone’s “homepage”. Here you click in the upper left corner on the displayed SIP account.
Here is a list of all SIP accounts stored in Linphone. You can deposit in Linphone namely several SIP accounts and then change if necessary in between.
But since you want to make calls over the SIP account of your FritzBox, of course, you can now select the previously set SIP account.
By clicking on “OK” you will …
… led back to the “homepage” of Linphone. From here you can now make and receive any number of telephone calls when a telephone call comes in. Just try it. 🙂

Have fun with the project

I hope everything worked as described. If not or you have any other questions or suggestions, please let me know in the comments. Also, ideas for new projects are always welcome. 🙂

P.S. Many of these projects - especially the hardware projects - cost a lot of time and money. Of course I do this because I enjoy it, but if you appreciate it that I share these information with you, I would be happy about a small donation to the coffee box. 🙂

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