asterisk users - Dec 2009 - rxgain / txgain for iaxmodem or hylafax

In trying to get the asterisk and faxing working
I had to resolve to using iaxmodem and hylafax.
I have incoming working, but outgoing the other fax rings
but it would appear from web searches that the fax signals
are too low to be "heard"

I can read about rxgain and txgain for zapata.
my fax setup goes direct from aterisk <-SIP-> SIP Provider <- Fax
Machine ->
It never touches my FXS and FXO card.


Thanks in advance

Barry

Barry Fawthrop wrote:
> I can read about rxgain and txgain for zapata.
> my fax setup goes direct from aterisk<-SIP->  SIP Provider<- Fax
Machine ->
> It never touches my FXS and FXO card.
>    
Faxing over SIP is not suggested, unless you are using something like 
T38.  Even in that scenario, some magic is required.

I'd suggest that you turn on the record function of iaxmodem and load up 
the in/out bound call audio in Audacity to compare volume levels.  The 
recordings to into /tmp or maybe /root/tmp:

cat ttyIAX01
device          /dev/ttyIAX01
port            4599
refresh         60
owner           root:root
mode            770
server          127.0.0.1
record
peername        iaxmodem.com01
secret          12345
cidname         SomeCompanyName.
cidnumber       269xxxxxxx
codec           slinear


Doug


-- 
Ben Franklin quote:

"Those who would give up Essential Liberty to purchase a little Temporary
Safety, deserve neither Liberty nor Safety."

On 12/27/2009 10:10 PM, Barry Fawthrop wrote:
> In trying to get the asterisk and faxing working
> I had to resolve to using iaxmodem and hylafax.
> I have incoming working, but outgoing the other fax rings
> but it would appear from web searches that the fax signals
> are too low to be "heard"
>    
A web search of what? Random uninformed comments,
perhaps?
> I can read about rxgain and txgain for zapata.
> my fax setup goes direct from aterisk<-SIP->  SIP Provider<- Fax
Machine ->
> It never touches my FXS and FXO card.
>    
FAX modems are designed to tolerate a very wide range of signal levels. 
Gain rarely matters much, except when it is set to some crazy high value 
that causes the signals to overload. There are numerous reasons for FAX 
over SIP to fail, which are well documented in any reasonable web search.

Steve