Hi Steve.
I checked into the legality of removing the header line, and it turns out this is only a problem for advertisements, which we are not doing.
As far as getting the header removed, I tried doing the following:
originate {ignore_early_media=true,absolute_codec_string='PCMU,PCMA',fax_enable_t38=true,fax_verbose=true,fax_use_ecm=true,fax_enable_t38_request=true,origination_caller_id_number='A CALLER ID',origination_caller_id_name='A CALLER ID NAME',call_timeout=120,fax_ident='a fax ident',fax_header=}sofia/gateway/outbound/+15555555555 &txFax('/tmp/sample.tiff')
Even if I remove the default headers in spandsp.conf.xml and fax.conf.xml I still get "SpanDSP Fax Header". I noticed that this is hardcoded in "src/mod/applications/mod_spandsp/mod_spandsp.c" line 527.
Am I not passing the null string properly somehow via originate? I noticed in my logs that there are many lines for "switch_event.c:1661 Parsing variable" for my other parameters, but not for my fax_header parameter.
Thanks!