Voice over IP

• Microsoft Real-Time Communications: Protocols and Technologies
• MSDN Webcast: Visual C# Express 2005: Creating an Instant Messaging Application Part 2 of 3
• SIP stack with SIP proxy - (VOIP)

Tech-invite

• ABNF Grammar for SDP -- Session Description Protocol (RFC 4566)
• SIP Protocol Structure through an Example

Service Providers

• Redspot Danish service provider
• everlove another Danish service provider

Soft Phones

SJphone® is a free VOIP softphone. It can be installed on:

Windows (XP SP2, 2000 SP4, Vista, Vista x64), Windows CE (Pocket PC, Windows Mobile), Linux, MAC

It supports both SIP and H.323 standards, and has a brilliant logging feature if you are having trouble getting a call through.

Note for Vista x64 (64 bit version) users:

On my Dell Lattitude I couldn't make a call or run the Audio Wizard, it crashed the program. I found a workaround:

1. Select: Menu -> To Advanced Mode
2. Select: Menu -> Options
3. Select: the Audio tab.
4. Select: Advanced Settings...
5. Uncheck: Enable Adaptive Echo Canceller

After that, I can make a call, and it is also possible to run the Audio Wizard.... I found this by trial and error, first I disabled everything in the 'Audio' tab, and reduced the sample rate, then I grdually enabled everything again.

• SJ Labs Homepage
• SJ Labs Download page

Links

• How to use the managed RTP API classes in .NET to create your multicasting systems

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