ABTO Software's VoIP SIP SDK allows quick VoIP softphone app development. Also you can use it when you need to add VoIP features to your software.

Quick facts about ABTO Software VoIP SIP SDK for Android:

Versions:

VoIP Video SIP SDK for Android
Standard VoIP SIP SDK for Android

Trial:

Download sample sip softphone on Google Play
Request trial SDK

Features:

All wide-spread Android versions (2.3.5+, 4.x, 5.x)
Support of SIP and RTP
UDP/TCP support
secure connection via SRTP and ZRTP;
STUN and other IETF standards (compatible with SER, OpenSER and Asterisk)
ICE support
SIP Registrar (SIP server) support
Audio and video calls
Single line support
DTMF
Status messages
User Agent name support
SIP port change
Available SIP port check
Bluetooth support
Second registration
Different networks support (WiFi, GPRS, 3G, EDGE)
Registration proxy support
Log support

Available codecs:

G.711-ALaw
G.711-muLaw
G.729
Speex
Theora
GSM
H.263
H.263+
H.264

Also you can use the following user features of VoIP Video SIP SDK for Android:

Set a custom ringtone
Use softphone with no registration (useful for calls in local network)
Communicate via IM chat
Check Call history
Store and use Contacts list
Play File to conversation
Put a call on Hold
Record a Call
Send DTMF (useful for calls to call center)
Enable/disable Video, Microphone and Speaker during the call


Sample app is available at https://play.google.com/store/apps/details?id=org.abtollc.videosoftphone

Скачать VoIP SIP SDK for Android бесплатно на странице загрузки.