CSipSimple is a Voice over Internet Protocol (VoIP) application for Google Android operating system using the SIP
It is open source and free software released under the GNU General Public License.
It relies on, and uses features provided by, the pjsip SIP stack.
Key features:
- Multi-codec support: Speex (narrow band, wideband), G.711 (u-law, a-law), GSM, iLBC, G.722, AMR (narrow band), iSAC.
A plugin also allows to use SILK (narrow band, wideband, ultra wideband), CODEC2, G.726, G.722.1. - Multi-account support : up to 10 accounts can be activated at the same time.
- Can use native audio driver
- STUN and ICE NAT traversal
- Integration with Android operating system with filters and rewriting rules
- A distribution of the software available on the website allow SRTP, SIP over TLS and ZRTP
- SIP-SIMPLE messaging
- An API for third party applications is available
Source: Wikipedia (CSipSimple)