VoIP/SIP Soft Phone C# WPF

Question

I need to write VoIP/SIP Soft Phone in C# using WPF interface with Audio support only. I need to have call transfer, call conference, and recording of conversations in mp3.

I've looked at VoIP SDK from ABTO LLC, but it is slow at application startup (30 seconds to start application, I think it's related to loading activex part of this sdk).

I've also looked at SIP.Net, but it's only for SIP and doesn't contain components for voice data transfer.

I have very limited time only 2 months from zero to fully working app.

What SDK can I use to accomplish this task?

Windows 7 must be supported.

Answer 1

We have done this using SipekSDK. It's written on top of famous pjSIP open source SIPClient project. It does all the operations you have mentioned in the question.

https://sites.google.com/site/sipekvoip/

Answer 2

What is the Sip server you are going to use ? If its not asterisk, you can have a look of microsoft's Lync here. You can download the Lync SDK and start exploring. Not just the audio call, Microsoft Lync has features like video call, chat, presence, conference etc.... and ofcourse connectivity to landline/pstn through voip providers

Another interesting article explaining the different SDKs for unified communications can be found here

Edit: If its for Asterisk, Sipek is the only available free opensource but we had lot of problems in installing in clients system like

1. C folder access
2. Poor device support
3. Port conflict- If any other voip app like qutecom runs on 5060, then Sipek wont run as the port is being used already.