In reply to a post by Anonymous:

So I increased the filtering power by using two adsl filters in serial!

Just wanted to say a massive THANK YOU!

Got my 7390 a couple of days ago and have been tearing my hair out trying to get rid of the hiss on the line when using the Fritz Box telephony. No joy until I found this - two filters, job done!

You have made me a happy, happy man

This is a common complaint with Fritzboxes on Annex A lines (Most of the world)

(They're developed by AVM in Germany which is Annex B only)

The quick fix is to stack a second filter on the analogue port of your existing filter and plug Fritz's analogue line into that. It works.


The longer term/better fix is for the Germans to sort out voiceband filtering inside the units and backoff the aggressive analogue line AGC within the units, but because they're an annex-B-only country, this kind of crosstalk is something they'll never encounter in the lab (Any telco engineer will tell you too much gain in a phone circuit is definitely a BAD thing. I've seen it take out microwave link monitoring systems in a previous life)

No disrespect to our german cousins, but they tend to be a bit..... "dogmatic" about many things, even when faced with a large number of cuistomer complaints they can't replicate inhouse. They have this theory that if reality doesn't fit their paper models then reality will have to change.

Edited by Stoatwblr (Fri 19-Apr-13 20:12:20)

You have a dodgy line. Have you had your telco check it?

In my experiences on a clean line Fritzs work better than anything else I've tried, but if there are any DC-type faults then speed goes down rapidly.

Losing broadband on ringing is symptomatic of an unbalanced line (or a bad filter, but I assume you're already changed that)

1: Ask your phone company to run a line check.

2: The extra filter goes on the INPUT to the fritzbox, not on Fon1 output.

Edited by Stoatwblr (Fri 19-Apr-13 20:18:14)