Код: Выделить всё
 core show translation 
         Translation times between formats (in microseconds) for one second of data
          Source Format (Rows) Destination Format (Columns)
           g723   gsm  ulaw  alaw g726aal2 adpcm  slin lpc10  g729 speex  ilbc  g726  g722 siren7 siren14 slin16
     g723     -     -     -     -        -     -     -     -     -     -     -     -     -      -       -      -
      gsm     -     -  1001  1001     5999  1001  1000  2000  6000     -     -  5999  1999      -       -   2999
     ulaw     -  2001     -     1     5000     2     1  1001  5001     -     -  5000  1000      -       -   2000
     alaw     -  2001     1     -     5000     2     1  1001  5001     -     -  5000  1000      -       -   2000
 g726aal2     -  3000  1001  1001        -  1001  1000  2000  6000     -     -  5999  1999      -       -   2999
    adpcm     -  2001     2     2     5000     -     1  1001  5001     -     -  5000  1000      -       -   2000
     slin     -  2000     1     1     4999     1     -  1000  5000     -     -  4999   999      -       -   1999
    lpc10     -  3000  1001  1001     5999  1001  1000     -  6000     -     -  5999  1999      -       -   2999
     g729     -  3000  1001  1001     5999  1001  1000  2000     -     -     -  5999  1999      -       -   2999
    speex     -     -     -     -        -     -     -     -     -     -     -     -     -      -       -      -
     ilbc     -     -     -     -        -     -     -     -     -     -     -     -     -      -       -      -
     g726     -  3000  1001  1001     5999  1001  1000  2000  6000     -     -     -  1999      -       -   2999
     g722     -  3000  1001  1001     5999  1001  1000  2000  6000     -     -  5999     -      -       -   1000
   siren7     -     -     -     -        -     -     -     -     -     -     -     -     -      -       -      -
  siren14     -     -     -     -        -     -     -     -     -     -     -     -     -      -       -      -
   slin16     -  5000  3001  3001     7999  3001  3000  4000  8000     -     -  7999  2000      -       -      -
Вызов от абонента А приходит от провайдера в кодеке - alaw. Далее - соединяется с клиентом Б по g729. Этот клиент делает перевод на В (Attended Transfer), разговаривает и кладет трубку. При соединении абонентов А и В слышимость в одном направлении - от А к В.
В консоли:
[Sep  6 14:22:20] WARNING[31416]: chan_sip.c:6290 sip_write: Asked to transmit frame type 64, while native formats is 0x8 (alaw)(8) read/write = 0x40 (slin)(64)/0x8 (alaw)(8)
[Sep  6 14:22:20] WARNING[31416]: chan_sip.c:6290 sip_write: Asked to transmit frame type 64, while native formats is 0x8 (alaw)(8) read/write = 0x40 (slin)(64)/0x8 (alaw)(8)
[Sep  6 14:22:20] WARNING[31416]: chan_sip.c:6290 sip_write: Asked to transmit frame type 64, while native formats is 0x8 (alaw)(8) read/write = 0x40 (slin)(64)/0x8 (alaw)(8)
[Sep  6 14:22:20] WARNING[31416]: chan_sip.c:6290 sip_write: Asked to transmit frame type 64, while native formats is 0x8 (alaw)(8) read/write = 0x40 (slin)(64)/0x8 (alaw)(8)
[Sep  6 14:22:20] WARNING[31416]: chan_sip.c:6290 sip_write: Asked to transmit frame type 64, while native formats is 0x8 (alaw)(8) read/write = 0x40 (slin)(64)/0x8 (alaw)(8)
[Sep  6 14:22:20] WARNING[31416]: chan_sip.c:6290 sip_write: Asked to transmit frame type 64, while native formats is 0x8 (alaw)(8) read/write = 0x40 (slin)(64)/0x8 (alaw)(8)
[Sep  6 14:22:20] WARNING[31416]: chan_sip.c:6290 sip_write: Asked to transmit frame type 64, while native formats is 0x8 (alaw)(8) read/write = 0x40 (slin)(64)/0x8 (alaw)(8)
[Sep  6 14:22:20] WARNING[31416]: chan_sip.c:6290 sip_write: Asked to transmit frame type 64, while native formats is 0x8 (alaw)(8) read/write = 0x40 (slin)(64)/0x8 (alaw)(8)
 
В настройках sip.conf, и в general и у каждого абонента стоит: 
disallow=all
allow=g729,alaw,ulaw
Пров передает только в alaw