HowTo: FritzBox – Use your own computer as a VoIP telephone via the FritzBox with Linphone

If you are one of the many owners of a FritzBox, you can set up an additional telephone extension on your computer with a few tricks. This means that you will be informed about calls on your Fritz Box on your computer and can also accept them if necessary. If you have connected a microphone and loudspeaker, you can also make calls via the computer.

Safety instructions

I know the following notes are always kind of annoying and seem unnecessary. Unfortunately, many people who knew "better" have lost eyes, fingers or other things due to carelessness or injured themselves. Data loss is almost negligible in comparison, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Because even the coolest project is not worth injury or other trouble.

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

Tools needed:

Materials needed:

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

Create a SIP account for the FritzBox

To set up another telephone extension on the FritzBox, you must first create another SIP account. This will then allow you to log in to your FritzBox with the corresponding login data.

To do this, log into the configuration interface of your FritzBox with your - already known - login data.
Once there, click on "Telephony"...
...and "telephony devices".
In the menu that opens, click on "Set up new device" 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 the type of phone you want to register. For a SIP account, select "Telephone (with and without answering machine)". To proceed to the next step, click on "Next".
In the next step, you then specify that this should be a "LAN/WAN(IP phone)". You can also set the name of the phone. Here you should specify a better name than "NameOfYourSipPhone". 🙂 To go to the next step, click "Next" again.
Then it's time to set a username and password for the SIP account. To do this, enter a user name under User name and a secure password under Password. To proceed to the next step, click on "Next" again.
In this step, you can specify which of your available - i.e. external - telephone numbers should be used to make an outgoing call to the SIP account to be created. At this point, you must select one of the available numbers. To proceed to the next step, click on "Next" again.
You must now make the same decision for incoming calls. This is because the FritzBox can - and in most cases this makes sense - forward external telephone calls to internally registered telephone extensions. At this point you can set which incoming calls from outside are forwarded to the SIP account to be created. Again, click on "Next" to proceed to the next step.
That's it for the settings. You will now be shown a summary of all the settings you have made. Check them again here and if you agree, click on "Apply".
However, before the new SIP account is created, you must fulfill a small security function. To do this, dial the displayed number with a telephone already connected to the FritzBox. You should only hear a "beep". This confirms to the Fritzbox that you really want to create an account and that no one from outside (via a security hole) wants to gain access to your telephone exchange.
As soon as you hear the "beep" on the phone, the view changes and confirms that the new account has been created. Now confirm this by clicking on "OK".
This will take you back to the list of available telephony devices. Your newly created SIP account will now be listed here as another telephony device (here "Name of your SIP phone").

Set up Linphone login on the FritzBox

Once you have created a SIP account on your FritzBox, it is now time to set up the software correctly on your computer. To do this, you first need the "Linphone" software. You can download this free of charge at download. How you can download and install the program is described in the articles Downloads/Uploads – How data comes and goes from the Internet and Install programs - an example described.

After you have installed and started Linphone, you should see this interface.
So that you can now register Linphone as a SIP client (i.e. telephone extension) on the FritzBox, you must first enter the SIP account login data in Linphone. To do this, first click on "Assistant".
...and click on "Use a SIP Account".
This will take you to an input screen where you can enter the previously created data for the SIP account.
Enter the login data of your SIP account here. With the login data from the example above, it would look like this. Once you have entered all the files, simply click on "USE"...
...and you will be redirected back to the Linphone "start page". Here you click on the displayed SIP account in the top left corner.
Here you will find a list of all SIP accounts stored in Linphone. You can save several SIP accounts in Linphone and then switch between them as required.
However, since you naturally want to make calls via the SIP account of your FritzBox, you now select the previously set SIP account here.
By clicking on "OK" you will be... will be redirected to the Linphone "start page". From here, you can now make or answer calls as you wish when a call comes in. Just give it a try 🙂

Have fun with the project

I hope everything worked as described for you. If not or you have questions or suggestions please let me know in the comments. I will then add this to the article if necessary.
Ideas for new projects are always welcome. 🙂

PS 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 think it's cool that I share the information with you, I would be happy about a small donation to the coffee fund. 🙂

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