asterisk users - May 2012 - OT - Incoming fax cuts ADSL line

Hi,

I'm facing a strange situation.
Though it's not directly related to Asterisk, I do think it is
interesting to this mailing list.


The setup is a single line which is split between an ADSL
modem/routeur and a fax machine (Asterisk was removed from the
equation).

Any time the fax machine rings (incoming fax), the ADSL service is
troubled to the VPN users are disconnected.
It can be reproduced at will.

I've changed the ADSL filter twice (a different unit, then a different
model) without any visible change.
What could explain this ?

Regards

----- Original Message -----
> Hi,
> 
> I'm facing a strange situation.
> Though it's not directly related to Asterisk, I do think it is
> interesting to this mailing list.
> 
> 
> The setup is a single line which is split between an ADSL
> modem/routeur and a fax machine (Asterisk was removed from the
> equation).
> 
> Any time the fax machine rings (incoming fax), the ADSL service is
> troubled to the VPN users are disconnected.
> It can be reproduced at will.
> 
> I've changed the ADSL filter twice (a different unit, then a
> different
> model) without any visible change.
> What could explain this ?
> 
I've experienced this quite a few times, and after working with a local
telco, it has become policy to not place ADSL on lines where fax is going to be
used. I'm unsure of the exact technical reasons behind this other than
'the fax signals/frequencies interfere with the ADSL signalling/frequencies
used on the circuit'. It sounds like you might want to separate your
fax/ADSL lines.

--Tim