[asterisk-users] spa8000 t38 faxing

[Larry Moore]

Perhaps this will help.

I have a SPA8800 which has 4 x FXS & 4 x FXO ports.

It took me some time to produce a working configuration.

In Asterisk I have the following where 904 is the extension of the 
fax-modem and itsp is you VoIP Service Provider.

sip.conf

  [general]
  .
  .
  faxdetect=no
  t38pt_udptl=yes,redundancy,maxdatagram=400
  .
  .

  [904]
  ; Cisco SPA8800 FXS Port 4
  ; Analogue FAX Modem attached
  type=friend
  defaultuser=904
  secret=<secret>
  call-limit=2
  qualify=yes
  canreinvite=no
  directmedia=no
  directrtpsetup=no
  ignoresdpversion=yes
  transport=udp,tcp
  host=dynamic
  context=<your_context>
  faxdetect=no

  .
  .
  [itsp]
  .
  .
  faxdetect=yes
  ignoresdpversion=yes
  .
  .


I am including information from my SPA8800 for one of the FXS ports I 
have a Fax Modem attached to, the key to getting it to work I believe is 
the "FAX Tone Detect Mode".

Audio Configuration

  Preferred Codec: G711a          Second Preferred Codec: Unspecified
  Third Preferred Codec: Unspecified    Use Pref Codec Only: no
  Silence Supp Enable: yes          Silence Threshold: medium
  G729a Enable: no              Echo Canc Enable: yes
  G723 Enable: no              Echo Canc Adapt Enable: yes
  G726-16 Enable: no              Echo Supp Enable: yes
  G726-24 Enable: no              FAX CED Detect Enable: yes
  G726-32 Enable: no              FAX CNG Detect Enable: yes
  G726-40 Enable: no              FAX Passthru Codec: G711a
  DTMF Process INFO: yes          FAX Codec Symmetric: yes
  DTMF Process AVT: yes          FAX Passthru Method: ReINVITE
  DTMF Tx Method: AVT              DTMF Tx Mode: Strict
  DTMF Tx Strict Hold Off Time:  40    FAX Process NSE: no
  Hook Flash Tx Method: None          FAX Disable ECAN: no
  Release Unused Codec: yes         FAX Enable T38: yes
  FAX T38 Redundancy: 1          FAX Tone Detect Mode: callee only
  Symmetric RTP: yes

Supplementary Service Settings

  CW Setting: no                Block CID Setting: no
  Block ANC Setting: no            DND Setting: no
  CID Setting: yes              CWCID Setting: yes
  Dist Ring Setting: yes            Secure Call Setting: no
  Message Waiting: no            Accept Media Loopback Request: automatic
  Media Loopback Mode: source        Media Loopback Type: media

Larry.