VoIP SIP SDK for iOS (iPhone and iPad) is a toolkit to quickly build SIP softphone client for iOS or add VoIP features into your app for App Store.

Operating System:

Mac OS X.

Development environments:
VOIP SIP SDK for iPhone on objective-C (Xcode);

VOIP SIP SDK for iPhone on Swift.

iOS versions:
VoIP SIP SDK for iOS 6;
VoIP SIP SDK for iOS 7;

VoIP SIP SDK for iOS 8.

Features:
supports 64 bit architecture;
SIP/RTP support;
STUN and other IETF standards (compatible with SER, OpenSER and Asterisk);
SIP Registrar (SIP server) – including Asterisk and ABTO Software SIP Server;
voice and video calls;
status messages;
work in background mode;
phone contacts book support;
secure connection via SRTP and ZRTP;
changing camera orientation;

switching between multiple cameras.

Available codecs:

H.263

H.263+

H.264

G.711-ALaw

G.711-muLaw

G.729

Speex

Theora

GSM