Пробую звонить с sip-девайса на другой девайс, Циска при поднятии трубки сбрасывает "на занято", а там где подняли - тишина.
Это проблема конфигурации циски или проблема и ИОСе ?
Если sip-прокси прописать не Циску а айпи-адрес сип-приставки, тогда при поднятии трубки звонок не срывается... в обеих направлениях.

1)5350 Software (C5350-IK8S-M), Version 12.3(14)T7, RELEASE SOFTWARE (fc2)

2)вот некоторые настройки циски:

voice call send-alert
voice rtp send-recv
!
voice service voip
allow-connections h323 to h323
allow-connections h323 to sip
allow-connections sip to h323
allow-connections sip to sip
fax protocol t38 ls-redundancy 0 hs-redundancy 0 fallback cisco
h323
sip
!
!
!
voice class codec 3031
codec preference 1 g711alaw
codec preference 2 g729r8
codec preference 3 g729br8
codec preference 4 g723r63
codec preference 5 g723r53
codec preference 6 g723ar63
codec preference 7 g723ar53
codec preference 8 g711ulaw
..
...
..

Вот два диалпира:

dial-peer voice 30045 voip
description calls with ippbx
destination-pattern 251561
voice-class codec 3031
session protocol sipv2
session target ipv4:192.168.172.101
session transport udp
dtmf-relay rtp-nte
!
dial-peer voice 30046 voip
description calls with ippbx
destination-pattern 252300
voice-class codec 3031
session protocol sipv2
session target ipv4:192.168.172.173
session transport udp
dtmf-relay rtp-nte

Ах да, и вот дебаги при сбросе:

SIP: (314215) Attribute ptime, level 1 instance 1 not found.
SIP: (314215) Attribute ptime, level 1 instance 1 not found.
SIP: (314215) Attribute ptime, level 1 instance 1 not found.
SIP: (314215) Attribute ptime, level 1 instance 1 not found.
..
..
SIP: Attribute ptime, level 1 instance 1 not found.
Aug 13 09:02:52.788: //314215/7B9651DEB393/SIP/Error/sipSPISetStreamInfo: Number of active streams is zero (0)!
Aug 13 09:02:52.792: //-1/xxxxxxxxxxxx/SIP/Error/sipSPIUcccause_to_sipcause: Unknown PSTN cause code from CCAPI:0
Aug 13 09:02:52.792: //314215/7B9651DEB393/SIP/Error/act_sentalert_disconnect: Disconnect cause from ccapi :16 and sip_disc_cause: 500
Aug 13 09:02:53.644: //-1/xxxxxxxxxxxx/SIP/Error/ccsip_new_msg_preprocessor: Could not find ccb for response