вот он ответил:
Сергей, я номер не вручную набираю, а выбираю из списка абонентов в панели телефонии, на кого перевести.
При попытке перевода
выводится сообщение «Переводим звонок консультативно 392 на номер 101», но в трубке звучит «Извините данный номер не существует пожалуйста попробуйте ещё раз».

А вот его попытка перевода со стороны АТС:

[2017-03-28 12:21:52] DTMF[6179][C-0000a918] channel.c: DTMF end '#' received on SIP/107-0001688c, duration 0 ms
[2017-03-28 12:21:52] DTMF[6179][C-0000a918] channel.c: DTMF begin emulation of '#' with duration 100 queued on SIP/107-0001688
c
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end emulation of '#' queued on SIP/107-0001688c
[2017-03-28 12:21:53] VERBOSE[6179][C-0000a918] res_musiconhold.c:     -- Started music on hold, class 'default', on SIP/392-00
01688b
[2017-03-28 12:21:53] VERBOSE[6179][C-0000a918] file.c:     -- <SIP/107-0001688c> Playing 'pbx-transfer.slin' (language 'ru')
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end '1' received on SIP/107-0001688c, duration 0 ms
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end accepted without begin '1' on SIP/107-0001688c
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end passthrough '1' on SIP/107-0001688c
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end '0' received on SIP/107-0001688c, duration 0 ms
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end accepted without begin '0' on SIP/107-0001688c
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end passthrough '0' on SIP/107-0001688c
[2017-03-28 12:21:53] WARNING[6179][C-0000a918] features.c: Extension '10' does not exist in context 'from-internal-xfer'
[2017-03-28 12:21:53] VERBOSE[6179][C-0000a918] file.c:     -- <SIP/107-0001688c> Playing 'pbx-invalid.slin' (language 'ru')
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end '1' received on SIP/107-0001688c, duration 0 ms
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end accepted without begin '1' on SIP/107-0001688c
[2017-03-28 12:21:53] DTMF[6179][C-0000a918] channel.c: DTMF end passthrough '1' on SIP/107-0001688c