Baklan

Baklan is an open source Voice Over IP phone (or SIP phone), available on Android devices, that makes possible to communicate freely with people over the internet.
Baklan is based on the renowned Linphone application with some custom additions and improvements.
Baklan makes use of the SIP protocol (an open standard for internet telephony) and can be used with any SIP VoIP operator, including our SIP audio service.

Main features:
- HD audio and rich codec support: Opus, SILK, G.711, Speex, iLBC, GSM
- Echo cancellation
- Microphone gain and speaker volume adjustments
- Secure communication with TLS and Secure RTP (SRTP) encryption protocols
- Presence using the SIMPLE standard with generic SUBSCRIBE/NOTIFY and PUBLISH messages
- Very intuitive UI
- Contact list integrated with primary account contact list
- Detailed call list and history
- Integrated billing information including balance, call rates, charges and payments
- Easy balance top-up
- Account wizard to create or restore account at Baklan Communications
- Can be used with any SIP provider
- Application debugging

Get a 0.5$ free bonus for test calls after creating your account.