fritzbox7050_2It is very likely that Fritz!Box, VOIP router made by German company AVM is one of the most popular SIP devices in the world. At least, I am sure that in Germany it is very common and there are plenty of people using it. The quality and the feature set of the device is remarkable, but one of the reasons for its popularity is the fact that some of German ADSL providers were giving away Fritz!Box for free together with the internet subscription.

 

While ago, I was looking for a solution to use my land line in Serbia to call friends and family while I was out of country. Of course, I could use standard VOIP providers, but it is still bit expensive to call land lines in Serbia as VOIP termination is monopolized by state telecom company. This is going to change soon I believe, but still you can’t call Serbia for 1 cent per minute or so, which is normal VOIP price for majority of European countries. I wanted somehow to connect to the land line in my house via internet, and from there call whomever I want at the low local tariff. After some online research, I decided to buy a Fritz!Box.

The price for new Fritz!Box WiFi, which is actually an ADSL router with build in SIP client and wireless access point in Belgian shop was quite high. It costs around 150 euro, and having in mind that idea for this project was to actually save on the phone bills, I was bit reluctant to cash out so much money. Of course, I started looking for used Fritz!Box on eBay, and very soon I’ve bought a Fritz!Box 7050 in black color from German seller for less than 50 bucks. At that time I didn’t realize that ADSL standards in Germany and rest of the Europe do not match – I thought that lower price for the used device in Germany was result of the fact that many people got the box for free and after changing internet provider they wanted to get rid of it and earn some cash. Of course, non-German sellers were asking much more money for their precious Fritz!Box, and if I could not order one from Germany I believe that I would rather go for a brand new device with warranty instead.

Can you imagine how big was my surprise when I got device with German-only interface, which does not work on my ADSL line? I can understand some German as I used to learn it in high school, but now it is a bit rusty. Anyway, I was able to configure the parameters of my ADSL line, but the damn thing did not want to synchronize with the Belgacom ADSL line. What else I could do – I plugged back my old router and searched for the fix. Luckily, there are many smart guys out there hacking these devices, and rather quickly (in couple of hours) I was able to load English firmware that supports non-German phone standards. So remember –if you buy Fritz!Box, the Annex-B device is supposed to work in Germany only, and for other European countries you would need an Annex-A box. But as I said, with little bit of effort you can manage to software update your German-speaking box to English web interface and work on Annex-A land lines. I will not spend time here to explain how to convert your device, as there are many different methods to do so depending on the model and firmware version. The best place for this is German forum www.ip-phone-forum – there is also English section and you will find many nice folks who would help you if you post a question.

Once the box was updated, it synchronized with the ADSL line immediately I entered the credentials, and I was online. It is possible to configure up to 10 different SIP accounts, and as I already had VoipBuster and VoipStunt logins, I quickly set them up. At the back of the Fritz!Box there are two ports for connecting analog phone, so I connected a wireless DECT base to one of the connectors. I logged in with my PC to another VoipBuster account, and tried to call directly from PC the account configured on the router. Of course, it worked very well – the phone started to ring and the sound quality was perfect.

Now it was time to test the function because of which I bought the Fritz!Box at the first place. I configured option “Call through” and specified that incoming calls to the VoipBuster line are routed to the land line. I configured the 4 digits pin code, and again used PC VoipBuster client to call the account configured on the Fritz!Box. Immediately after pressing the dial button, I heard special short tone signalizing that I need to enter PIN. I typed in 4 digits, and then press 0 to get access to the land line (as explained in the product manual). And voila – I heard dial tone from my land line on the speakers of my PC. First number I tried to dial was my mobile, and on the screen I saw the caller ID of my land line.

Good – it worked flawlessly. Happy and satisfied with the device, I realized that it could be good idea to buy one more Fritz, so I could keep one of them in Brussels apartment and the other in my parents’ house in Serbia, as originally planned. In next few days I bought one more Fritz!Box on German eBay, and I managed to buy it for only 25 euro, as it was device without WiFi. I already had WiFi access points in Serbia, so the cheaper version was more than enough. The second box was as well for German market, but having the experience with the first one, it didn’t take me much time to convert it to English language and Annex-A. Before I left to Serbia, I just managed to enable the remote access to my Belgian Fritz!Box so I could control it from remote location. From some reason, this feature is not accessible from the web interface – by default you could manage your Fritz only from the internal network, and there is no option to allow remote management. Again I had to search for solution online, and it was not too difficult to figure out that only way to enable the remote access was to connect to the Fritz!Box with telnet and edit couple of files by hand. I didn’t mention that Fritz!Boz is actually running on Linux, so most of standard UNIX command worked, including editor. However, there is also special version of editor called nvi (instead standard vi), and the difference is that with nvi you could edit the file directly in the flash memory. I will not write here how to do that, if you need it I am sure you can find it quickly using your favorite search engine.

fritzscreenThe final challenge I had was to get direct access to my land line in Belgium using the wireless handset in Serbia and vice versa, with the help of two Fritz!Boxes and internet. It was easy to call the Voipbuster user from PC with their proprietary VOIP application, or even using some other soft phone like SJphone for example. There it is enough just to enter your username@voipbuster.com and direct SIP call would be established. However, the handset connected to the Fritz!Box does not have alphanumeric keyboard, so the solution I am using is based on the built-in phonebook of Fritz!Box. For example, in the first position of the phonebook I would enter something like sip:username@voipbuster.com and save it, and then from the handset I would use **701 to dial to the first phonebook entry. Similar, for second phonebook number the shortcut on the handset should be **702. You can see how the configuration looks like on the attached screenshot.

And that’s it! Now I can use my land line in Serbia when I am in Belgium, and from Belgium I can also utilize the land line in Serbia to have cheap calls to my friends and family. I would also like to be able to establish direct call between two Fritz!Boxes without help of the SIP provider like VoipBuster, but until now I did not figure out how to do that (if possible). If any of you guys reading this articles know how to do that, please post it here as comment.