Q.931
An International Telecommunication Union Specification for establishing, maintaining, and clearing Integrated Services Digital Network (ISDN) connections. See ISDN.

QAM (quadrature amplitude modulation)
A modulation technique used to transmit 9,600 bits per second over a 2,400-baud line. See modulation.

QBE (query by example)
A query method (also known as "find similar") that enables the user of an information retrieval system to obtain search results by using examples — such as text strings or document names — that are characteristic of the information sought.

QCIF (Quarter Common Intermediate Format)
Part of the H.261 video format standard. QCIF offers 176x144 pixel resolution, one-quarter that of Full CIF (FCIF). See CIF and FCIF.

QMF (Query Management Facility)
An IBM mainframe query and report-writing product for relational database management systems.

QOS (quality of service)
A negotiated contract between a user and a network provider that renders some degree of reliable capacity in the shared network.

QPM (QoS Policy Manager)
A Cisco Systems offering.

QSIG
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.

query
A request for information placed to a computer system or database. Queries may be performed by human beings (for example, a Web user entering a query into a search engine), but are also commonly performed by computers themselves (for example, a program placing an automated query to a database).