Blink 2.3

Blink is a state of the art, easy to use SIP client. It is elegant, intuitive to use and feature-full.
Blink can be used on the LAN without an account or can be configured with a SIP account obtained from a SIP service provider.
For support go to http://icanblink.com/help-pro.phtml
* Support for multiple accounts
* High Definition VoIP (G.722 and speex codecs)
* PSTN Telephony (G711, GSM and iLBC codecs)
* Support for external USB microphones and speakers
* Multiparty Conferencing for all supported media
* Speakerphone with Acoustic Echo Cancellation
* iCloud support for account syncing
* Keychain password storage
* Voiceover accessibility support
* Address Book contacts integration
* Answering Machine and Auto-Answer
* Dialpad, DTMF, Hold, Transfer and Recording
* Many Call Automation Features
* Presence (RLS and XCAP)
* Instant Messaging (MSRP protocol)
* File Transfers (MSRP protocol)
* Contacts Management (XCAP protocol)
* Directory Services (LDAP protocol)
* Screen Sharing (VNC over MSRP)
* XMPP interoperability (using sip2sip.info)
* Comprehensive History Viewer for all media types
* Fine-grained settings and logging for SIP experts
The complete features list is available at http://icanblink.com/blink-pro.phtml

Known interoperability issues:
http://projects.ag-projects.com/projects/blinkc/wiki/KnownIssues