How to build a softphone (using SIP protocol) using C#

c# voip sip
Srikanth V M picture Srikanth V M · Jul 1, 2009 · Viewed 28.9k times · Source

I have this challenge to build an sip softphone using c# or .net technologies.

Please guide me the technology, requirements and specifications that is needed to build such.

Possible requirements:

Supported codecs:

G.722.1, G.723.1, G.726, G.728, G.711, G.729, G.723.1, iLBC,: G.711 (A and m-law),G.729A/B/D/E, AMR, GSM 6.10/EFR, iLBC, Speex

  • Voice:

    Real time Quality Monitoring (MOS) 3 independent phone lines
    Auto-Answer/Do Not Disturb Call
    Forwarding Full Duplex Audio
    Recording compress the audio data.

  • Fully SIP compatible softphone/dialer for PC2Phone and Mobile2Phone (iPhone, Nokia N95) application with symbian s60 , full source code should provide.

  • Compatible with Windows 2000/XP/2003/Vista/Mac

  • NAT/Firewall traversal feature

  • Works with any 3rd party SIP Server

  • Supports SIP outbound proxy

  • Displays callers account balance

  • Displays call credit time

  • Automatic Echo Cancellation

  • Automatic jitter buffer adjustment

  • Last number Redial

  • History of 10 last dialed numbers

  • Quick dial user list

  • Quick provision for customers, only user name and password required

Answer

abhilash picture abhilash · Jul 1, 2009

Here are a few pointers

  • See this article on Code Project for implementing an SIP stack in C#
  • See this post for audio compression using LAME

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