[Asterisk-Users] Problems with fax failing when bridged across TDM400Pvers E

[Andrew Kohlsmith]

On Tuesday 22 November 2005 08:54, Chuck Bunn wrote:
> What I do not understand is how dropped packets prevent the fax from
> working. Faxes are designed to adopt to noise on the line by reducing
> their connection speed. It seems like their is something else besides
> packet loss going on here. Also why would the board work for receiving
> faxes but not sending???

Faxes are designed to work around the noise and other signal problems inherent 
in analog telephony.  VOIP introduces an entirely different set of noise 
factors that fax machines are frankly ill-equipped to deal with.  Jitter and 
dropped packets are the biggest of these issues.

Now which version of Zaptel are you running (not Asterisk, Zaptel) -- was it 
part of the Asterisk 1.0.x series, are you running 1.2 or CVS HEAD?  It is a 
possibility that this issue is fixed now in CVS HEAD (possibly 1.2 as well, I 
haven't been keeping track), so it is advisable to try the latest version of 
Zaptel.  You do not need to upgrade to the latest Asterisk in order to use 
the latest Zaptel.

-A.