Q Signaling

What Does Q Signaling Mean?

Q signaling (QSIG) handles digital private branch exchange (PBX) signaling and is an Integrated Services Digital Network (ISDN) signaling standard built according to Q.931 specifications.


QSIG is used in Voice over Internet Protocol (VoIP) networks, virtual private networks (VPN) and high-speed and multi-application networks for enterprises, universities and government entities.

Techopedia Explains Q Signaling

QSIG ensures that the following Q.931 functions are managed in networks that use equipment from different vendors:

  • Setup signal: Indicates established connection
  • Call-proceeding signal: Indicates destination call processing
  • Ring-alert signal: Alerts caller regarding ringing destination device
  • Connect signal: Indicates destination device call receipt
  • Release-complete signal: Transmitted at the end of a call by the source or destination.

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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.