[asterisk-users] Unknown RTP codec 100 received

[Thomas Artner]

Hi!

I have an analog fax machine connected to a sipura ATA which is connected to 
my asterisk box.
In my asterisk box I have a digium card for a connection to the public 
telephone network (analog).
On this digium card is also a us robotics sportster modem (analog) connected.

My problem:
I can send faxes from the analog faxmachine to the us robotics modem, but when 
I try to send a fax to someone else (via the public phone network) it fails 
and I get the following error message: Unknown RTP codec 100 received.

Does anyone have an idea why faxing to the analog modem works perfectly, and 
why it fails if i try to send one "outside" ?

thx in advance,
tom