New VoIP SIP SDK for Windows – 20141203

ABTO Software released new version of VoIP SIP SDK for Windows 4.8.1203.4. Recent changes of VoIP SIP SDK for Windows:

  • improved playing of long wav files;
  • added ability to use different video devices in different sdk instances created in signle app;
  • added new method AssignVideoWindow([in]LONG ConnectionId, [in] LONG hVideoWindow);  it allows assigning video window and establishing connectionId.

Download the updated version of VoIP SIP SDK for Windows.

New VoIP SIP SDK for Windows

ABTO Software announces new version of VoIP SIP SDK for Windows (both 8 lines and 64 lines versions with/without video and video conference).
New VoIP SIP SDK for Windows version includes updates for latest 6 months. You are welcome to download the latest SDK on our website.

You can have a look at the log of the most important changes of VoIP SIP SDK for Windows here:

284. Redesigned setting ‘CallInviteTimeout’
Now SDK allows to apply it before call and use different timeouts for different calls.

285. Improved sending video encoded with H264
Modifed packetization code

288. Added ability autodetect network interface when proxy server is set (instead of registration domain)

289. Improved code of receiving sound from audiodevice.
Added ability to detect how long component is waiting for data from device
and disable its functionality.

290. Modified Unregister procedure.
Now SDK always appends SIP header “Expire=0″

292. Added new method
UpdateCall(LONG ConnectionId, BSTR FromDisplName);
293. Added new event:
OnRemoteAlerting2(LONG ConnectionId, LONG LineId, LONG responseCode, BSTR reasonMsg);

294. Improved method StartCall (StartCall2).
Added one more argument ConnectionId as return result, which allows easier track events from created connection.
295. Improved handling Trying message, now SDK returns proper connectionId in event OnRemoteAlerting
296. Improved threadsave – added code which has help to avoid possible crashes with HangUpLastCall

297. Fixed bug with clearing/creating multiple calls
When create new calls fast enough, it’s possible situation when call is allowed, but mixer port is not ready.

298. Fixed sound issue with repeatedly playing wav files
299. Fixed crash when make multiple calls and start playing files

302. Fixed possible crash in method StartRecording, when user passes path, which doesn’t exist

303. Fixed playing default ring tone
304. Added log file item to track playing mode (detect MixerFilePlayerEnabled)
305. Modified method SendRequestInfo, added argument ‘string contentType’

307. Fixed bug with simultaneous playing multiples files
when method PlayFile invoked after established incoming call
308. Fixed bug with receving DTMF as SIP INFO without specified tone duration

309. Improved method SendRequestInfo (Brian), now it allows to set fully qualified content type
Improved event OnReceivedInfoEvent – now it returns fully qualified content type

310. Updated help file

311. Added new method GetSIPMessageLine

312. Modified CAbtoPhone::ApplyConfig
Now SDK will throw exception when app tries to apply new settings during active call(s).

New trial SIP SDK for iOS

Please visit our Download page to try updated trial VoIP SIP SDK for iPhone.

New softphone in Google Play

We are happy and proud to invite you to try our updated sample sip softphone for Android. The main updates are better video  and secure connection support. The latest softphone version is available at Google Play.


We often receive the following questions about our ABTO Software’s VoIP SIP SDK for Windows:

  • is it implemented as native SIP DLL SDK or as ActiveX (COM) object.
  • how to integrate SDK into own application.

The answer is that VoIP SIP SDK for Windows is implemented as ActiveX simple object and compiled into native dll. It means that SDK can be used as ActiveX (COM) component which requires registration on client computer via regsvr32 tool. But it is not a single way. The SDK also exports methods and can be used as native SIP DLL SDK without registration. Standard SDK setup contains source code of both implementations.

So, it means that VoIP SIP SDK for Windows can be used in your app via ActiveX interface and via native DLL interface (exported functions as SIP DLL SDK).

SIP ZRTP client

ABTO Software’s VoIP SIP SDK is proud to present a new feature – ZRTP support for mobile platforms: iOS and Android.Using our SDK you are able to build custom sip zrtp client for iOS and Android.

Currently realization allows ZRTP secure peer-to-peer connection. Also it works in the situation when sip server does not influence the messages that it transfers. We are working on other cases of such connections.

To try this feature and purchase our SDK please proceed to the contact form or download the corresponding SDK for iOS and Android.

Early media use

You can use VoIP SIP SDK to make a custom intercom.
Obviously you can make a connection to communicate before you open the door.
However, one of the basic features of this solution is to be able to see the person near door before actually making a connection.
This feature is typically called early media.

How to implement it for Android:

when received incoming call in Android app invoke method:
phone.answerCall(183, true);

This method sends to remote side SIP request “183 Session progress+SDP”,
which allows start sending audio\video in both directions, but call still not answered.
Then you can answer or reject call.
If you have more questions please contact us.

STUN use

We are receiving many questions about STUN use.

STUN means Session Traversal Utilities for  NAT (Network Address Translator).

When using STUN is a good idea: If you do not receive video and audio because remote side can not send media. The reason could be that SIP sends local IP address. So you can try to enable STUN and input one of the following settings:


If you have more questions please contact us.

SDK Update for Android

New version of VoIP Video SIP SDK for Android was finally released.

The latest version of the SDK includes many updates including features requested by our customers for recent 6 months: change of log level and ability to rotate video during the call. Also we added the following new methods to AbtoPhoneConfig: getAccountExpire, getAccountDisplayName, getAccountCallURL, isAccountRegistered.

VoIP SIP SDK for Android - Sample SettingsFor newcomers and repeated customers here is the full list of our technical features of SDK for Android:

  • STUN support
  • ICE support
  • User Agent name support
  • SIP port change
  • Available SIP port check
  • Bluetooth support
  • Second registration
  • UDP/TCP support
  • Different networks support (WiFi, GPRS, 3G, EDGE)
  • Registration proxy support
  • sRTP support
  • Log support

VoIP Video SIP SDK for Android - SampleAlso 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

Codecs support: Speex, GSM, PCMU, PCMA, ISAC, ILBC, G.729, H.264, H.263.
To try the latest version of VoIP Video SIP SDK for Android please proceed to our download page.


Development Environments:

  • Visual C++ / C++ / C# .NET
  • VB.NET / VB 6.0
  • Java
  • JavaScript / HTML / HTML5
  • Flash
  • Borland Delphi

Company details:

ABTO Software is the only owner and distributor of VoIP SIP SDK. The company also develops other products and offers software development services. Read more on