[SOLVED] Cannot receive fax

till now i could not set up fax with asterisk.
i just begined at january with asterisk and freepbx, so i thought to wait till freepbx 2.7 promised easy fax settings, to try my luck with fax.

i upgraded to freepbx 2.7 today.

i have asterisk
freepbx core 2.7.0RC1.1
fax configuration
freepbx framework 2.7.0RC1.1
360 MB RAM XEN VPS hosting
Ubuntu 9.10 32 bit with 2.6.31-302-ec2 kernel
i install res_fax.so and res_fax_digium.so (core2 as bench proposed) and i have the one free licensed channel.
i have installed dahdi (MusicOnHold and Conferences work)

at freepbx i have settings an incoming route to go directly (without fax detection) to a fax receiving user, to whom i enabled fax and put destination email.

i call from a normal pstn line fax machine to my incoming voip DID which is conected to asterisk/freepbx

i get no receiving fax tone signal. should i expect one? i just hear silence after the rings when trying to send faxes

debuging logs show that it tries to send fax, but fax fails.

fax show stats show that all faxes are failed.
both modules are loaded.

asterisk cli reports:
Got SIP response 420 “Option Disabled” back from
wikipedia says 420 Bad Extension (Bad SIP Protocol Extension used, not understood by the server)
t38pt_udptl=yes is set both at general sip settings and at did provider settings.
even the did provider itself, proposes this settings.

any idea?

after disabling t38pt_udptl, i hear fax signal
fax starts transmition but stops with "FAXSTATUS=FAILED LICENSE EXCEEDED"

so it seems i have 2 problems

  1. t38 does not work for reasons i dont know
  2. g711 answers but then stop, for unknown reasons also
    any idea?
    thanks a lot


FAX Statistics:

Current Sessions : 0
Transmit Attempts : 0
Receive Attempts : 19
Completed FAXes : 4
Failed FAXes : 15

Digium G.711
Licensed Channels : 1
Max Concurrent : 1
Success : 0
Switched to T.38 : 0
Canceled : 0
No FAX : 3
Partial : 0
Negotiation Failed : 0
Train Failure : 1
Protocol Error : 0
IO Partial : 0
IO Fail : 0

Digium T.38
Licensed Channels : 1
Max Concurrent : 0
Success : 0
Canceled : 0
No FAX : 0
Partial : 0
Negotiation Failed : 0
Train Failure : 0
Protocol Error : 0
IO Partial : 0
IO Fail : 0


Registered FAX Technology Modules:

Description : Digium FAX Driver
Capabilities : SEND RECEIVE T.38 G.711

1 registered modules

Free fax licenses: 1
Total licensed ports: 1


i fixed the licensing problem
now it shows FAX_RX_EMAIL=email
it starts to receive fax, then a lot of messages like that:

Channel ‘SIP/xxxxxxx’ fax session ‘7’, [ 007.647927 ], channel sent 26 frames (520 ms) of energy.
– FAX handle 1: [ 008.586858 ], STAT_EVT_T4_EXP st: WT_DIS_RSP rt: XXXXNT4X
– FAX handle 1: [ 008.586907 ], STAT_EVT_FSC_ERR st: WT_DIS_RSP rt: RXXXNFRX
– FAX handle 1: [ 008.586925 ], STAT_INFO_CSI
– FAX handle 1: [ 008.586988 ], STAT_INFO_DIS

*** 45 seconds with similar messages *********

Channel ‘SIP/xxxxx’ fax session ‘7’, [ 045.512601 ], channel sent 149 frames (2980 ms) of silence.
Channel ‘SIP/xxxxx’ fax session ‘7’, [ 046.032351 ], channel sent 26 frames (520 ms) of energy.
– FAX handle 1: [ 047.789373 ], STAT_EVT_HW_CLOSE st: WT_HW_CLS rt: WCLSNCLS
– FAX handle 1: [ 047.789467 ], STAT_SES_COMPLETE
– Channel ‘SIP/xxxxx’ FAX session ‘7’ is complete, result: ‘FAILED’ (FAX_NO_FAX), error: ‘T1_TIMEOUT’, pages: 0, resolution: ‘unknown’, transfer rate: ‘2400’, remoteSID: ‘’
– Executing [[email protected]:4] Set(“SIP/xxxxx”, “FAXSTATUS=“FAILED FAXOPT: error: T1_TIMEOUT status: FAILED statusstr: FAX_NO_FAX””) in new stack
– Auto fallthrough, channel ‘SIP/xxxxx’ status is ‘UNKNOWN’
– Executing [[email protected]:1] GotoIf(“SIP/xxxxx”, “”"?failed") in new stack
– Goto (ext-fax,h,103)
– Executing [[email protected]:103] NoOp(“SIP/xxxxx”, “FAX “FAILED FAXOPT: error: T1_TIMEOUT status: FAILED statusstr: FAX_NO_FAX” for: "[email protected]” , From: “222222” <22222>") in new tack

well the good news is that the FreePBX part of things looks like it is working. However, I suspect the fact that you are trying to receive a fax, without T38, in a virtual environment, sent over VoIP might have a lot to do with your problems. You have almost everything working against you with those conditions.

kartaka -

Can you share with the community what your licensing issue was in case someone else runs into this problem?

i dont know
maybe one of the following reasons:

  • for some reason register tool did not finish successfully, the first time and i did not realize it
  • maybe that the email set at freepbx for delivering or originating faxes, was different than the one registered at digium website. does it matter?


  1. do u mean that i receive fax with g711 and it cannot work idealy under these situations? wouldn’t i be able to receive at least 1 out of 10 faxes?

  2. why i cannot receive faxes with t38?

why when i t38pt_udptl=yes
i get no incoming fax tone signal and at cli the debuging info says:
Got SIP response 420 “Option Disabled” back from xx.xx.xx.xx

thanks a lot :slight_smile:


your first question on receiving faxes, I can only say do a little bit of searching on the web wrt to receiving faxes over VoIP in a perfect environment, then toss in the fact that you are in a virtual machine…

For your second question, I have no idea as I have never done any fax reception with T38. It sounds like an Asterisk configuration issue. It may be your issue or may be our issue, I don’t know. When you find out, please let us know what you had to do to get it working and if you believe it is something that the module could help with or at least try to detect inabilities and provide warnings, file a ticket with details so we can have a look.

ok thanks

  1. could you please propose me some good asterisk or fax-over-ip forums?

  2. finally i cannot receive faxes with one voip provider, but i can receive locally or through another voip provider.
    i talk abou g711.
    what specifications should i ask from voip provider to be able to receive faxes?

  3. when set at t38, is fax-for-asterisk supposed to produce signal or not?
    the fax machine that sends the faxes but be also t38 compatible?

  4. i received faxes before, but i dont receive them to my email through that perl scripts, although i generally take emails from freepbx for voicemails,updates etc.



i hope this will fix some problem. i ll try later and tell u.

no, it did not fix.

– Executing [[email protected]:1] GotoIf(“SIP/xxxxxxx”, “0?failed”) in new stack
– Executing [[email protected]:2] ExecIf(“SIP/xxxxxxxxx”, “”"?system(/var/lib/asterisk/bin/fax-process.pl --to "[email protected]" --from "[email protected]" --dest “s” --subject “New fax from xxxx " --attachment fax_xxx.pdf --type application/pdf --file /var/spool/asterisk/fax/xxxxxx.xxx.tif)”) in new stack

this does not send me email

although if i manually execute the fax-process.pl command, i get the fax to email



have a look at this thread:


I notice you are running For someone who is very new to all this, you are doing yourself a dis-service as 1.6.X has a lot of issues.

Asterisk considers 1.6.0.X, 1.6.1.X and 1.6.2.X as DIFFERENT mainstream releases. Assuming you require 1.6+ (which is the case for T38 I think), you should stick with the most stable of the 1.6 releases and not be on the bleeding edge. I don’t know which of the three is considered more stable but finding out which one from your peers and using that one would be best. Ideally, you could stick with 1.4.X as it is MUCH more stable then the issues that people continue to come up with in 1.6+.

thanks a lot for your advices and kindness