Noisy fixed-line on Fritzbox

I have a Fritzbox 7140 which works pretty well as a VOIP gateway.

However, I am getting lots of noise on the fixed-line POTS phone line that runs through the box. Hissing, etc. Sounds a bit like the sound you get when using a phone without a DSL splitter/filter. I have tried 3 different splitters but with no improvement just in case that was the problem.

Anyone had this issue and managed to solve it?

Thanks.

Many ATA boxes provide FXO connectivity to the FXS port not by switching but rather by a conversion FXO<>FXS. So when a call is made to the PSTN phone using the FXS connected handset it is converted from analogue to voip, passed to the FXO port and converted back from voip to analogue PSTN. This usually makes the call noisier and sometimes introduces echo. "Comfort noise" (can be adjusted in the setup) is often added to voip so that callers do not think that they have been disconnected when the line is quiet. You should also make sure that there is not a mismatch between your PSTN line and the Fritz.

Thanks for the prompt reply.

The background noise is actually very intrusive, making the caller difficult to hear. Unfortunately the Fritzbox does not appear to have settings to adjust to improve this, unless they are hidden and undocumented.

Probably best tackled here ...

http://www.avm.de/en/service/support/index.html

Official manufacturers' 'support' sites and forums such as this used by real users are worlds apart.

The AVM site has some ideas but not solutions.

I was hoping to find ideas from fellow VOIPers trying to find their way past the relentless positive gloss put on their products by manufacturers.

One of the reasons I come to VOIP USER is to see past the spin.

talkeasy :

Thanks for the prompt reply. The background noise is actually very intrusive,

The noise should not be that loud. With my system (Linksys) it is easy to tell the difference between a direct PSTN call and through the ATA but certainly not obtrusive and with some tinkering with the settings easy to ignore. Here are a couple of links that might help.

http://www.hostingforum.ca/104425-fritz ... ction.html
http://nl.nntp2http.com/telecom/2006/11 ... 945fb.html

Quote:

One of the reasons I come to VOIP USER is to see past the spin

Totally agreed, but just now and then an obscure problem comes along that both requires the input of the makers of the device and indeed they benefit from the knowledge that their design has a fault in some user circumstances.

What you are experiencing is definitely not normal, whilst there is a lively proportion of Fritz users here on VU I would take a guess that none of them have ever suffered the same problem.

AVM are pretty innovative in Voipspace and IMHO not prone to spin or evasion - in short I think they will want to know about your experiences.

For info, we have about 70 FritzBox users logged into our server right now and it's always been a very popular device (SIPgate were giving them away for free not too long ago).

I've never seen this complaint about them, and if it was common we almost certainly would have in the past.

My guess is a hardware fault.

There are a few comments on the web from people with the same problem. But it seems in some of the cases that it was just a bad arrangement of cables. Fritz boxes seem to be as rare as hens teeth over here.

My guess is its an impedance missmatch. as Like you say Dean they are fine on sip but the issue seems to be pstn, I ssume they localise them in some way.

Ian

Have you checked the PSTN line connecting to a regular phone (remove the ATA). I have a problem with the wiring in my house from time to time. The cheap wiring that the phone company used slowly corrodes causing the PSTN line to crackle while it has no effect on the DSL signal. (I expect that is something that you have already checked). If you have a Cordless phone set try that as well as I think you are less likely to get an impedance mismatch if that is the problem. If you can, reducing the audio volume in the ATA often helps.

The POTS phone line works fine when not routed through the Fritzbox. Indeed it also works fine with other devices like my Handytone 386 ATA.

Seems the mostly likely issue is either a faulty box (already on my second after the first was damaged in transit) or the myriad of cables and power adaptors in close proximity. My next test will be to isolate out the Fritzbox into a clean electrical environment.

On the wider issue of reliable equipment - I spent several months researching around the web for an ATA/Router that suited my particular requirements, i.e. a small device that did not require a separate PC always on to power Asterisk yet still provided enough flexibility for SIP switching around the home and home office.

The Fritzbox 7140 has been on the PCW Magazine Top List for months and there has been nothing but positive comments about the unit posted around the web. However, I have had a series of on-going issues with DSL synchronisation (fixed by a firmware release last month), reliability and the fixed-line issue mentioned in this thread.

Do I have naive expectations about what can be achieved by our tech equipment or are we being duped by the marketing departments into buying half thought through and tested technology?

I have found the Linksys 3102 to be very reliable. I have used voip twice now to call the telephone company to report that my PSTN line was not working! The sound quality using Voipuser is excellent. It just sits there and runs. It transfers voip<>PSTN and does everything needed. The weak point there was the lack of a comprehensive manual! I think you might have been unlucky with the Fritzbox. It looks like a well thought out device from my reading of the manual. It even has a clever baby minder function built in.
You mentioned the GS386 ATA. I have had experience with the GS286 ATA (in the UK) and that did pick up mains hum (50 Hz) from the house wiring unless carefully placed. I hope tidying the wiring works for you.

One other thought.... You are in the UK with those odd plugs and ring capacitors? Perhaps the problem is with the connecting cable from the wall to the ATA. Worth a check.

Just in case someone is still reading this thread, here's my suggestion.

I recently upgraded my FritzBox ATA to a FritzBox Fon Wlan 7170 and had exactly the same problem. On one of my phones I got a huge constant frequency "noise" while using the landline (on incoming calls as well).

I tried to switch around my phones to see if it was the FritzBox, but the other phone worked in the same plug as the previous that didn't work, so it was not related to the FritzBox. I finally found the culprit: I had another DSL filter between the FritzBox phone line and the phone. Taking it out fixed the problem

Hope this can help someone! I sure was mad at this problem...!

I have also the same problem with the fritzbox wlan 7140. VOIP connection out f.e. with VOIPUSER is excellent quality.

But incoming fixed line is with distortion sounds. And the caller doesn't hear this distortion sounds, only me, the receiver seems to hear them.