FYI CentOS No FAX modules detected. res_fax_spandsp.so missing

chris_c_

Active Member
Joined
Aug 19, 2010
Messages
509
Reaction score
67
The following error message appears, when you enter into the Extension application, and either create a new extension, or Edit and existing extension.

ERROR: No FAX modules detected!
Fax-related dialplan will NOT be generated.
This module requires Fax for Asterisk (res_fax_digium.so) or spandsp based app_fax (res_fax_spandsp.so) to function.


Installer script: IncrediblePBX13-12R-OAUTH.sh
OS: CentOS 7 32 bit

Why was the option "--disable res_fax_spandsp" added tothe menuselect portion of the installer script ?
 

restamp

Member
Joined
Apr 24, 2016
Messages
97
Reaction score
52
I presumed it was because we use Hylafax and don't need the built-in Fax modules. I resolved the error by going to [ Admin > Module Admin > Settings ] and disabling "Fax Configuration". For good measure, I went to [ Admin > Feature Codes ] and disabled "Dial System FAX", although this was probably not necessary.

If anyone knows of any negative repercussions for having done this, please let me know, but it seems to have stopped the complaints without affecting anything else and I am still able to Fax through the Hylafax/AvantFax packages.
 
  • Like
Reactions: wardmundy

chris_c_

Active Member
Joined
Aug 19, 2010
Messages
509
Reaction score
67
I presumed it was because we use Hylafax and don't need the built-in Fax modules. I resolved the error by going to [ Admin > Module Admin > Settings ] and disabling "Fax Configuration". For good measure, I went to [ Admin > Feature Codes ] and disabled "Dial System FAX", although this was probably not necessary.

If anyone knows of any negative repercussions for having done this, please let me know, but it seems to have stopped the complaints without affecting anything else and I am still able to Fax through the Hylafax/AvantFax packages.
It sounds like you're probably using a physical hardware fax modem to fax thru HylaFax/AvantFax?

Because spandsp is the software fax modem module, which you would require for sending/receiving faxes over a soft voip line.

Details :
http://community.freepbx.org/t/how-to-add-fax-capabilities-to-freepbx/25478

t38modem uses asterisk's t38 "pass through" ability but requires a T38 compliant VSP. (voip service provider)

iaxmodem will do T30 faxes over a good g711 connection.

both need spandsp compiled and working with asterisk compiled against it.
Again, who disabled spandsp in menuselect in the CentOS installer script? Why?
 

wardmundy

Nerd Uno
Joined
Oct 12, 2007
Messages
15,071
Reaction score
2,597
We use the iaxmodem software for software-based faxing with HylaFax and AvantFax. FreePBX doesn't know how to detect iaxmodem support. @restamp provided the fix if the erroneous error is bothersome.
 
Last edited:

chris_c_

Active Member
Joined
Aug 19, 2010
Messages
509
Reaction score
67
We use the iaxmodem software for software-based faxing with HylaFax and AvantFax. FreePBX doesn't know how to detect iaxmodem support. @restamp provided the fix if the erroneous error is bothersome.
FreePBX Extension setting to enable Fax detection, used to be enabled, because spandsp was present, and it worked fine on ubuntu 14.04. What happened that it was disabled on the CentOS installer ?
 

krzykat

Guru
Joined
Aug 2, 2008
Messages
1,509
Reaction score
395
Location
South Florida
I use the fax portion in asterisk and it does work. But, Yes - you must recompile asterisk for SpanDSP - its been this way for probably over a year now that I remember.
 

chris_c_

Active Member
Joined
Aug 19, 2010
Messages
509
Reaction score
67
@restamp @krzykat @wardmundy
It appears that, iaxmodem includes a complete (yet slightly outdated) copy of spandsp, compiled into itself, inaccessible to asterisk.
To provide asterisk with direct fax receiving ability, you have to compile/install a second copy of spandsp!!
o_O
 

krzykat

Guru
Joined
Aug 2, 2008
Messages
1,509
Reaction score
395
Location
South Florida
AvantFax/HylaFax provide direct fax receiving capability. Always have. Think of it as apples and oranges, both good fruits... but different.
I'm guessing here, but I think he's complaining about - Why is PIAF almost forcing a user to use Hylafax by not including spandsp into the original make, its there, just not compiled in for asterisk. Anyone wanting to use the native fax in asterisk must recompile. I've actually had good success on inbound faxes being handled by asterisk and then being e-mailed out for quite some time, so for me, its actually easier than using hylafax.
 
  • Like
Reactions: chris_c_

chris_c_

Active Member
Joined
Aug 19, 2010
Messages
509
Reaction score
67
@krzykat That's right. The IncrediblePBX installer script downloads spandsp rpm, installs it, and then disables the spandsp option on the compile of asterisk. What issue resulted in someone having turned off asterisk's use of spandsp by default?
 

dicko

Still learning but earning
Joined
Oct 30, 2015
Messages
640
Reaction score
234
For the brave of heart there is also t38modem that integrates equally well with hylafax as a sip connection, trivial on Debian (apt-get install t38modem) . a total PITA on RH stuff however as you will need to compile it yourself : -) you can easily bypass asterisk/FreePBX totally for faxing through a VSP that supports t38 if you want to, otherwise it is just another SIP endpoint to asterisk utilizing asterisk's native t38 pass through ability.
 
Last edited:

chris_c_

Active Member
Joined
Aug 19, 2010
Messages
509
Reaction score
67
For the brave of heart there is also t38modem that integrates equally well with hylafax as a sip connection, trivial on Debian (apt-get install t38modem) . a total PITA on RH stuff however as you will need to compile it yourself : -) you can easily bypass asterisk/FreePBX totally for faxing through a VSP that supports t38 if you want to, otherwise it is just another SIP endpoint to asterisk utilizing asterisk's native t38 pass through ability.
Thanks, saw your post from last year :

Code:
t38modem -tt -o /var/log/t38modem0.log --no-h323 -u T38modem --route "modem:.*=sip:@127.0.0.1:38000" \
--route "sip:.*=modem:" --sip-listen udp\$127.0.0.1:38000 --ptty +/dev/ttyT0 --sip-register [email protected],yourpassword > /dev/null 2>&1 &
http://community.freepbx.org/t/t38-fax-detection/27763/3

Seems like t38modem should probably replace iaxmodem in the installer script since it offers the reliability of t38 vs iaxmodem which doesn't have the t38 feature instead using straight g711 pcm audio subject to jitter delay and packet loss.
 
  • Like
Reactions: wa4zlw

dicko

Still learning but earning
Joined
Oct 30, 2015
Messages
640
Reaction score
234
There is sometimes a gotcha there, although t38modem is designed to fall-back to t30 if necessary, there are some vsp's who advertise t38 support but do it incompletely and your t38modems will get confused by such signalling (who can blame it ? ) , for those I rely on iaxmodem and a good network. Hylafax, well configured, can easily handle such rerouting after a defined number of failures.
 
Last edited:

dicko

Still learning but earning
Joined
Oct 30, 2015
Messages
640
Reaction score
234
the logs that t38modem spits out can be extensive, I suggest you look in them first, IMHO as most t38 problems are self induced by the operator, of course YMMMV . . . We get +99% success using it (bloody doctor's offices) the few that fail are often those with the VA , go figure :)
 

chris_c_

Active Member
Joined
Aug 19, 2010
Messages
509
Reaction score
67
@krzykat @dicko
There is sometimes a gotcha there, although t38modem is designed to fall-back to t30 if necessary, there are some vsp's who advertise t38 support but do it incompletely and your t38modems will get confused by such signalling (who can blame it ? ) , for those I rely on iaxmodem and a good network. Hylafax, well configured, can easily handle such rerouting after a defined number of failures.
Some? LOL - I think it's closer to most don't do it right.
Sounds like you're saying the script should install both t38modem and iaxmodem. And each one should fallback to the other after X failures from the same incoming CID/StationID.
Or for outgoing, after X failures to transmit to the same destination number.
 

Noxee

New Member
Joined
Oct 20, 2016
Messages
5
Reaction score
1
Location
Montreal, QC, Canada
I use the fax portion in asterisk and it does work. But, Yes - you must recompile asterisk for SpanDSP - its been this way for probably over a year now that I remember.
Any chance you could post some instructions on how to recompile Asterisk for SpanDSP?
 

chris_c_

Active Member
Joined
Aug 19, 2010
Messages
509
Reaction score
67
Any chance you could post some instructions on how to recompile Asterisk for SpanDSP?
To do a quick recompile of Asterisk in order to have the spandsp support added:

$ cd /usr/src/asterisk-*
$ ./configure
$ make menuselect

Ensure that under the Resource Modules heading, the section for spandsp looks like this:

[*] res_fax_spandsp

If you see this instead:

XXX res_fax_spandsp

It means that Asterisk was not able to find the spandsp library.

Once you have verified that Asterisk can see spandsp, you are ready to recompile. Save and exit from menuselect, and run the following:

$ make
$ make install

You can verify that spandsp is working with Asterisk by issuing the following command from the Asterisk CLI:

*CLI> module show like res_fax_spandsp.so

At this point the SendFAX() and ReceiveFAX() dialplan applications will be available to you.
 

Members online

PIAF 5 - Powered by 3CX

Forum statistics

Threads
22,317
Messages
136,958
Members
14,542
Latest member
k0dean