[Asterisk-Users] PSTN Incoming call on real line disrupts VoIP call over DSL circuit - EXPLAINED

[Hadar Pedhazur]

Juergen K. Zick wrote:
> HI,
> 
> well, that was what I expected in my posting yesterday. For me, your 
> wiring looks strange. Here in Germany, we have "spiltters" connected to 
> the incoming line which have two outputs: A high pass filter output for 
> the DSL signal and a low pass output with DC  pass-through for the POTS 
> signal. the DSL output is being connected to the DSL-modem and the POTS 
> output will feed your internal POTS wiring.

The only jack that has both a phone and the DSL connector indeed has a 
splitter on it, provided by Bellsouth.

> Therefore, there is _NO_ filter needed on each POTS outlet, because 
> there is nothing to be filtered out on your internal line anymore.

You may be correct. I am definitely _not_ familiar enough with DSL. 
However, 5 years ago, I had a DSL line in my apartment, and I was 
specifically told by the installation tech that I needed a filter on 
_any_ jack that had a real phone connected to it. That may not have been 
necessary, or perhaps isn't necessary any longer, or perhaps varies by 
provider, but that's what I was told at the time, and that's what I did 
(with no problems).

The filters on the phone jacks that didn't have the modem connected were 
not splitters, just single filters.

> Seen from my German wiring knowlegde, your cabling is wrong and causes 
> the interruptions on the DSL service.

That's definitely possible, just not my personal (single point!) experience.

> Don`t you have something like a "spiltter" available ? It should be the 
> _ONLY_ filter on your incoming line and then the DSL-modem and the POTS 
> phone should be connected to it ...

OK, it would be easy for him to remove the other filters temporarily and 
test again.

Thanks!

> --Jürgen

>> Replying to my own post (and my most recent follow-up). I have now 
>> confirmed 100% that the DSL modem gets a _new_ IP address every time 
>> his "real" phone gets answered, or hung up! This (of course) disrupts 
>> the audio coming from to him, since the sending machine (Asterisk in 
>> my case), no longer has the correct IP address to send to him.
>>
>> I lowered his registration from the default 1 hour to 1 minute, so 
>> after we're disconnected, I can see that he's re-registering with a 
>> new IP address, each and every time :-(.
>>
>> I told him to call Bellsouth and ask about a Static IP address, but I 
>> don't know if they offer it, or how much they charge.
>>
>> While this one isn't "solved", it's at least "explained".
>>
>> Thanks to everyone who responded!