Interactive Voice Response Engine and Application Framework


ezIVR is SIPez's interactive voice response (IVR) server. It is a very flexible SIP-based IVR engine that runs scripted IVR applications. ezIVR uses host based media processing, so it does not require any special purpose hardware. It runs on standard Windows and Linux hardware. ezIVR is built on the highly interoperable, standards-compliant SIP User Agent from the sipX open source project using the sipXtapi API. sipX has been tested in all 23 of the SIPit SIP Interoperability Testing events, the first of which was held in April 1999.

ezIVR supports narrow band, wideband, and HD voice to provide high quality audio at the most efficient bandwidth for your needs. ezIVR uses the SIPez Media Engine (SME) to optimize VoIP audio quality with superior active gain control (AGC), voice activity detection (VAD), adaptive dejitter, and packet loss compensation (PLC). ezIVR supports a wide range of codecs with additional codecs easily added due to SIPez's codec plugin framework.

ezIVR's scripting engine is flexable and highly extensable to satisfy your IVR application needs within a wide range of scalability from low end systems running on Intel Atom-based processors to large scale deployments running with high availability across multiple servers using multi-processor, multi-core systems.


  • High interoperablity between disparate SIP end points
  • Bridge the void of non-overlapping support of wideband codecs without the PSTN audio downgrade
  • Large set of supported audio codecs
  • Scalable from embedded devices to multi-server, multi-1000 line solutions


ezIVR is ideal for running a wide variety of applications such as:

  • Conference bridge
  • Auto-attendent
  • Voice mail
  • Call center
  • Calling card
  • Predictive dialing
  • Announcement services


  • Wideband and HD voice
  • Conference bridge
  • Conference create
  • Conference destroy
  • Conference join
  • Conference split
  • Call create
  • Call destroy
  • Outbound dialing
  • Back to back user agent (B2BUA)
  • Barge-in
  • DTMF collection
  • DTMF generation
  • Prompt playback
  • Voice record
  • Hold
  • Unhold
  • Forward
  • Transfer
  • Optionally registers as a SIP client
  • Supports most standard shells and scripting languages
  • Command line integration
  • Script to script RPC
  • Configurable internal processing sample rate (e.g. 8000, 16000, 32000, 48000 samples/second)
  • Compliance with SIP RFCs 3261, 3262, 3263, 3264, 3265
  • Compliance with RTP RFCs 1889, 1890, 3550, 3551

Standard Codecs

  • SPEEX wideband
  • SPEEX narrowband
  • G.722 wideband
  • G.722.2 (AMR wideband)
  • iLBC (RFC 3951)
  • DTMF Events (RFC 2833, 4733)
  • G.711

Optional Codecs

  • SPEEX ultra-wideband
  • AMR
  • GSM (FR 06.10)
  • G.726
  • G.729
  • Others easily added


The SIPez IVR engine is available on Windows XP and Linux operating systems. SIPez is happy to provide a quote for a port to other platforms.