VoIP SIP SDK for Windows
Windows
Development environments
All versions of Windows OS, including Windows 8.1 and 64 bit systems
License Details
No per-seat licensing
10 days fully functional
All versions of Windows OS, including Windows 8.1 and 64 bit systems
Development Features
C#, C++, VB.NET, VB 6.0, and Delphi support
ActiveX, COM, and plain dll files
support of SIP DLL SDK (via native dll interface)
NAT (Network Address Translation) support
Encryption on the basis of sRTP, DLS, and DTLS
DTMF (Dual Tone Multi Frequency) support
SIP Authentication
Codecs management
Log file on/off setting
Noise reduction (supression)
AGC (Auto gain controller) support
Adaptive silence detection
Adaptive jitter buffer
Software volume control (including Mute Sound)
Playing file into conversation
Recording conversation into file
Redirection of calls to other phone lines
Call history and address book ready
Available Codecs
H.263
H.264
G.711 (ALaw, muLaw)
G.726 (16k 24k 32k 40k)
G.729A
G.723
OPUS
iLBC
LPC-10
Speex (Narrow, Wide)
L16
RFC4733 DTMF tones
GSM
Protocols Support
SIP (Session Initiation Protocol)
RTP (Real-time Transport Protocol)
SDP (Session Description Protocol)
TCP (Transmission Control Protocol) /UDP (User Datagram Protocol)
STUN (Session Traversal Utilities for NAT)
ICE (Interactive Connectivity Establishment)
End User Features
Generally support of all kinds of Internet connections
Multiline support
Multiple sip accounts registration
Multi-party voice conference
SIP Registrar support (compatibility with most of SIP servers including Asterisk)
Works under firewall
IM interface
Selecting of media input and output devices
Custom ringtone support
Configuration saving and loading
Updates VoIP SIP SDK for Windows
Stability Updates VoIP SIP SDK for Windows
September 16, 2026
Windows SIP SDK update 150926 is now available. This maintenance release focuses on stability, reliability and performance improvements. Download the latest update for Windows. Changes in this build – Improved SDK stability and reliability – Internal performance optimizations – Maintenance updates for smoother SDK operation – General improvements to ensure continued compatibility and reliable performance
Learn moreUpdates of VoIP SIP SDK for Windows
October 24, 2024
Try new features by downloading our latest update for Windows. Changes list: added ICE support to x64 version of SDK fixed crash on handling multiple call redirects fixed crash on handling hold when call not answered yet fixed playing ringtone on receiving/ending multiple calls added ability to use random RTP port numbers (set phone.Config.RtpStartPort=0)
Learn moreUpdates of VoIP SIP SDK for Windows
February 13, 2024
Please download our latest update of VoIP SIP SDK for Windows. Change log: Minor adjustments and stability enhancements
Learn more
ABTO Software VoIP SIP SDK for Windows provides capabilities to build a custom SIP softphone with support of multiple line voice/video calls and video conference, IM chat, multiple SIP accounts, presence, and voice mail, or add VoIP features to your custom IVR/intercom/CRM software.