VoIP integration

Promwad Electronics Design House developed its own software solution based on the Asterisk application to integrate VoIP into network devices.

Asterisk PBX is an open source software operated by Linux that allows you to implement the following functions.

Asterisk PBX functionality

  • voice mail
  • call processing
  • interactive voice response (IVR)
  • music on hold (MoH)
  • call history (CDR)
  • support for audio codecs (G.711, G. 723, G.726, G.729, GSM)
  • comfort noise generation (CNG)
  • line echo cancellation (LEC)
  • voice activity detection (VAD)
  • jitter buffering, faxing (T.30 and T.38) and other

In its VoIP software solution Promwad implemented the support for SLIC (subscriber line interface circuit) to connect analog telephones to network devices. The choice of SLIC depends on the desired number of connected analog telephone sets.

Promwad has experienced in working with SLICs manufactured by Silicon Laboratories Inc., Zarlink Semiconductor Inc.

VoIP software components scheme

Picture. VoIP software components



For VoIP software Promwad developed the following components:

  • The SLIC driver for the sound transmission and calls detection
  • The Asterisk channel driver for communication between the SLIC driver and the Asterisk application
  • Dialing rules generator for Asterisk
  • The web-based interface for Asterisk and SLIC configuration management


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