Our VoIP SIP SDK provides a powerful and highly customizable solution to quickly add SIP based dial and receive phone calls features in your software applications. It accelerates the development of SIP compliant soft phone with a fully-customizable user interface and brand name.

The Abto LLC VoIP SIP SDK contains a high performance VoIP conferencing client capable of delivering crystal clear sound even for both low and high-bandwidth users and SIP compatible devices (hardware and software). It enables a worldwide communication over the internet or intern networks either by speaking and delivers superior voice quality. It supports DTMF, adaptive silence detection, adaptive jitter buffer!

Abto LLC VoIP SIP SDK is based on IETF standards (SIP, STUN, etc.), so it should be compatible with other standard based products such as Asterisk, OpenSER other.
Dynamically loadable codecs
Registrar support
STUN support
Samples on Delphi, C#, VB, VB.NET, C#, HTML
echo cancelation
support of playing audio files
Hold/Retrieve with sample
Record conversation into WAV
Delphi sample updated
VB sample updated
HTML JavaScript sample updated
Extended OnIncomingCall event arguments
Call transfer support
Added status code on call reject
Added Unauthorized and Trying events for user registration
Fixed bug with default sound device
Fixed to be recognized as valid ActiveX component
Samples updated
Mute Sound
VPN support
Fixed VB6 compilation issue
Support of Authorization Id
FAX recognition
Noise reduction
Auto gain
Local number parameter
Help updated
Jitter buffer parameters
Windowless samples on C++ and .NET

Version 2.1:
- IM interface added
- fixed issue with RFC4566
- Codec disabling
- Help updated
- Samples updated
- Playback of different formats of WAV files
- Software volume control

Ссылка: http://www.abto..wnload/SIP_21.zip