[SOLVED] Trouble with fax gateway

There are several schemas :

  1. Asterisk 10.1.3 - sip,g729,t38 - Asterisk 10.1.3
    Generating faxes on the first and take them on the second, faxes are 100%.

  2. Asterisk 10.1.3 - sip,g711a,t30 - Asterisk 10.1.3 (circuit through the pri)
    Asterisk 10.1.3 equiped with 2 span (pri). Generating faxes on the first and passing through the pri take them on the second, faxes are 100%

  3. Asterisk 10.1.3 - sip,g729,t38 - Asterisk 10.1.3 (circuit through the pri)
    Asterisk 10.1.3 equiped with 2 span (pri). Generating faxes on the first and passing through the pri take them on the second, faxes are 30-40%.

  4. Asterisk 10.1.3 - sip,g729,t38 - Asterisk 1.4.29 (with patch from Attrafax) (circuit through the pri)
    Asterisk 1.4.29 equiped with 2 span (pri). Generating faxes on the first and passing through the pri take them on the second, faxes are 80-90%.

In what may be the cause of the problem in the third case ?

After install last version of SpanDSP ( 0.0.6pre20 ) , faxes 80-90%.