A private branch exchange (PBX) networking protocol produced by the European Computer Manufacturer's Association. The QSIG standard defines a private signaling system for interconnecting PBXs to achieve corporate networking. See PBX.

Q (point of the ISDN model) Signalling. Signalling standard. Common channel signalling protocol based on ISDN Q.931 standards and used by many digital PBXs.

Q (point of the ISDN model) Signaling. Signaling standard. Common channel signaling protocol based on ISDN Q.931 standards and used by many digital PBXs.