Open Source SIP "PBX"?

I am looking for some piece of Open Source software to implement a SIP "PBX" on a Unix system. Ideally, it should be able to do the following:

  • provide SIP registry server to local SIP phones
  • register itself to potentially multiple outside SIP registry servers to receive SIP calls from outside under different SIP addresses (which providers might have mapped to PSTN numbers).
  • Provide some screening logic for incoming SIP calls
  • Forward incoming outside SIP calls to local SIP phones according to a definable logic
  • Doing so it should act as a media gateway as well, i.e. it should be a complete application-level gateway between local SIP phones and the outside world (involves e.g. some SIP header rewriting)
  • It should do so as well for outgoing calls
  • It should be able to implement a private numbering plan/call routing logic for outgoing calls including the use of different SIP caller addresses depending on the destination.
  • It should be able to do codec conversions, i.e. allowing the use of a compressing codec for outside incoming and outgoing calls with a local SIP phone which only supports G.711.
  • It should be able to color traffic by setting the IPv4 ToS bits to a defined value for outgoing VoIP packets, thus setting a basis for CoS-aware QoS.

Is Asterisk a good starting point to look for these features? Or is there any other software you can recommend taking a look at?

Reply to
Georg Schwarz
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Reply to
Wolfgang Barth

You might want to check out Sip Express Router (free, go google, no link handy) or sipXpbx (free as well, at

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'll have to look through the features list, but I believe most or all of those things are covered. These are lighter weight, probably better supported on non-Linux platforms, but lack the hardware support and some modularity of Asterisk (if you need those).

Reply to
B.M. Wright

The asterisk seems to be good and gives above functions But now a new group has statred for SIP PBX with opensource SW and you can visit the following site. It is also SIP IPBX.

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Reply to



Yes, have a look at

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too and CVS version. A newer version of YATE with lots of new features is also under development.

Reply to
Dr Balwinder S Dheeman

do they include a media gateway? Can they act as an application level proxy for SIP calls?

Reply to
Georg Schwarz Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.