Q & A

Question and Answer. A teleconferencing term . During a lecture style teleconference, typically only the session sponsor can transmit audio; the other participants can listen, only. Q & A allows the other participants to signal via their touchtone pads their desire to ask a question. The session moderator/speaker can accept that request off-line, screen the question, and allow the participant to ask it on-line, as appropriate.

Q Band

A range of radio frequencies in the 40 GHz and 50 GHz range, also known as the V Band. The "Q" is a random, arbitrarily-assigned designation with its roots in the context of military security during World War II.

Q Bit

The qualifier bit in an X.25 packet that allows the DTE to indicate that it wishes to transmit data on more than one level. It is Bit 8 in the first octet of a packet header. It is used to indicate whether the packet contains control information.


ITU-T Recommendation. UPT Stage 2 for Service Set 1 on IN CS1 Procedures for universal personal telecommunication functional modelling and information flows.


ITU-T Recommendation. B-ISDN signaling ATM Adaptation Layer Overview.


ITU-T Recommendation. B-ISDN Adaptation Layer - Service Specific Connection Oriented Protocol.


ITU-T Recommendation. B-ISDN Adaptation Layer - Service Specific Connection Oriented Function for Support of signaling at the UNI.


ITU-T Recommendation. Broadband integrated services digital network (BISDN), Extension to the SS7 B-ISDN user Part (B-ISUP): signaling capabilities to support the indication of the statistical bit rate configuration 2.


ITU-T Recommendation. B-ISDN user Part - Support of negotiation during connection setup.


ITU-T Recommendation. Broadband integrated services digital network (BISDN), Extensions to the signaling system No. 7 B-ISDN user Part (B-ISUP) : Modification procedures with negotiation.


ITU-T Recommendation. Switched virtual path capability.


ITU-T Recommendation. Soft PVC capability.


ITU-T Recommendation. The signaling standard for ATM to support Switched Virtual Connections. This is based on the signaling standard for ISDN.

Q.2934 ITU-T

ITU-T Recommendation. Broadband - Integrated services digital network (B-ISDN) digital subscriber signaling system No. 2 (DSS 2) - Switched virtual path capability.


ITU-T Recommendation. Additional signaling procedures for the support of the SBR2 and SBR3 ATM transfer capabilities.


ITU-T Recommendation. Digital subscriber signaling system No. 2 - Connection characteristics negotiation during call/connection establishment phase.


ITU-T Recommendation. Broadband integrated services digital network (BISDN) digital subscriber signaling system No. 2 (DSS 2) connection modification - ATM traffic descriptor modification with negotiation by the connection owner.


ITU-T Recommendation. The signaling standard for ATM to support Switched Virtual Connections. This is based on the signaling standard for ISDN.


ITU-T Recommendation. Interworking between ISDN access and Non-ISDN access over ISDN user part of signaling system 7 - Support of VPN applications with PSS1 information flows.


ITU-T Recommendation. Messaging Transfer Part (MTP) of SS7.


ITU-T Recommendation. PBX Application part of SS7.


ITU-T Recommendation. Signaling Connection Control Part (SCCP) part of SS7.


ITU-T Recommendation. Telephone User Part (TUP) part of SS7.


ITU-T Recommendation. ISDN Supplementary Systems part of SS7.


ITU-T Recommendation. Data User Part (DUP) part of SS7.


ITU-T Recommendation. Network element information model for SCCP accounting and accounting verification.


ITU-T Recommendation. MTP Protocol tester.


ISDN User Part (ISUP) part of SS7.


ITU-T Recommendation. Signaling System No. 7 application transport mechanism.


ITU-T Recommendation. Signaling System No. 7 - Application transport mechanism - Support of VPN applications with PSS1 information flows.


Transaction Capabilities Application Part (TCAP) part of SS7.


Monitoring, Operations, and Maintenance part of SS7.


Test Specifications part of SS7.


ITU-T Recommendation. Specification of TMN applications at the Q3 interface: Call detail recording.


ITU-T Recommendation. Usage of cause and location in the digital subscriber signaling system No. 1 and the signaling system No. 7 ISDN user part.


ITU-T Recommendation. Q.921 defines the ISDN frame format at the data link layer of the OSI/ISDN Model. It contains address information. The ITU-T/OSI Layer 2 protocol used in the D channel. It is synonymous with LAPD.

Q.922 Annex A.

ITU-T Recommendation defining the structure of Frame Relay frames. All Frame Relay frames entering the network automatically conform to this frame structure.


Q.931 is the powerful message-oriented signaling protocol in the PRI ISDN D- channel. It is also referred as ITU-T Recommendation I.451. This protocol describes what goes into a signaling packet and defines the message type and content. Specifically, Q.931 provides:

  • call setup and take down.

  • called party number, with type of number indication (private or public).

  • calling party number information (including privacy and authenticity indicators).

  • bearer capability (to distinguish, for example, voice versus data for compatibility check between terminals.

  • status checking (for recovery from abnormal events, such as protocol failures or the manual busying of trunks), and

  • release of B-channels and the application of tones and/or announcements in the originating switch upon encountering errors.

    Q.931 makes it possible to interwork PBX features with features in the public network. In addition to offering users more access to a wider range of services, this interaction, according to Northern Telecom, will improve the revenue potential of service providers. Service provided over PRA, using Q.931, include:

  • access to the public network, such as equal access, WATS, DDD, international DDD, dial-800 and other special number services and operator assisted calls.

  • access to and from such private networks as Northern Telecom's Meridian Switched Network (previously call Electronic Switched Network ” ESN), tandem tie networks, and extension dialing network, and

  • integration of voice and circuit-switched data traffic (up to 64 Kbps). The Q.931 protocol also enables corporations to use B-channels ” that is voice and data channels ” in ways currently not possible. Today, for example, a separate trunk from the PBX to the central office is often required for each different service, such as voice, data, foreign exchange, 800-service. With PRA, one common trunk between the PBX and the central office can carry multiple call types. Moreover each B-channel within the PRA trunk can be assigned dynamically to carry whatever service is needed at the moment.


ITU-T Recommendation. The signaling standard for Frame Relay to support SVCs. This is based on the signaling standard for ISDN.




In the NTSC color system the Q signal represents the chrominance on the green- magenta axis.


The first quarter of the calendar year. It's typically the period from January 1 to March 30. But for companies with a different reporting year ” perhaps one ending on June 30, their first quarter would be the months of July, August and September. Q2 is the second quarter, Q3 is the third quarter, etc. etc.


See Q1.


See Q1.


See Q1.


Quality Assurance.


Quadrature Amplitude Modulation. A sophisticated modulation technique, or compression technique, using variations in signal amplitude and phase, that allows multiple bits to form a single "symbol," which then is impressed on a single sine wave. "Quadrature" refers to the fact that four (i.e., "quad") distinct amplitude levels are defined. 16 QAM creates a symbol of 4 bits through 16 distinct signal points, or variations in amplitude and phase, thereby yielding a data rate of 9600 bps over a 2400 Hz carrier. (Note: 2 to the 4th power ” i.e. 2 x 2 x 2 x 2 ” equals 16. Thereby, to place 4 bits on a sine wave, 16 signal points are required.) 64 QAM creates a symbol of 6 bits through 64 distinct plot points, yielding a data rate of 14.4 Kbps. (Note: 2 to the 6th power equals 64.) 128 QAM creates a symbol of 7 bits through 128 distinct plot points, yielding a data rate of 16.8 Kbps. (Note: 2 to the seventh power equals 128.) As the carrier frequency varies from 2400 Hz, which is the standard usable bandwidth for a voice-grade channel, the potential bit rate increases or decreases accordingly . See also Long Reach Ethernet and QSAM.


See Quantity Above Threshold Indicator.


Query By Example. A database front-end that requests the user to supply an example of the type of data he wants to retrieve. Typically, the user forms a query by filling in a table with examples of the requested information. IBM created QBE in the 1970s to simplify the process of retrieving information from mainframe databases; it was later implemented on the PC platform in such products as dBASE and Paradox. See also SQL.


A test message containing the "Quick Brown Fox" text. Used to test data terminals. The text is "The Quick Brown Fox jumped over the lazy dogs." It contains every letter of the alphabet. Check it out.

QC Laser

Quantum Cascade laser, a new type of semiconductor laser that works like an electronic waterfall. According to Bell Labs who invented the QC laser, it is the world's first laser that can be tailored to emit light at a specific wavelength at nearly any point over a very wide range from the mid- to far- infrared spectrum. This can be done by simply varying the layer thickness of the laser, using the same combination of materials. Conventional semiconductor lasers, widely used in other applications such as lightwave communications and compact disk players, operate at wavelengths from the near infrared to the visible. When an electric current flows through the QC laser, electrons cascade down an energy staircase . Every time they hit a step they emit an infrared photon, or light pulse. At each step, the electrons make a quantum jump between well defined energy levels. The emitted photons are reflected back and forth between built-in mirrors, stimulating other quantum jumps and the emission of other photons until the amplified pulse escapes the laser cavity . The QC laser was invented by Federico Capasso and Jerome Faist in collaboration with Debbie Sivco, Carlo Sirtori, Al Hutchinson and Al Cho, according to AT&T Bell Labs.


Qualcomm Codebook Excited Linear Prediction. A proprietary voice compression algorithm developed by Qualcomm for use in digital telephone, CDMA (Code Division Multiple Access) wireless cellular, voice storage, and speech synthesis systems. According to Qualcomm, QCELP can operate in either Fixed Rate Mode or Variable Rate Mode. In Fixed Rate Mode (FRM), speech can be encoded at rates of 4, 4.8, 8, or 9.6 Kbps. In Normal Variable Rate Mode (NVRM), the data rate automatically adjusts from 800 bps to 8 Kbps. In Enhanced Variable Rate Mode (EVRM), the data rate automatically adjusts from 800 bps to 9.6 Kbps every 20 milliseconds (ms). When in Variable Rate Mode, the vocoders (voice coders) code speech at under 7 Kbps in continuous speech applications and at under 3.6 Kbps in typical two-way telephone conversations, without degradation in speech quality. See also CELP.


Quarter Common Intermediate Format, a mandatory part of the ITU-T's H.261 standard which requires that non-interlaced video frames be sent with 144 luminance lines and 176 pixels at a rate of 30 fps (frames per second). QCIF provides approximately one quarter the resolution of CIF, but requires about one quarter the bandwidth. It works quite nicely for small-screen display devices.


Queuing Delay: Queuing delay refers to the delay imposed on a cell by its having to be buffered because of unavailability of resources to pass the cell onto the next network function or element. This buffering could be a result of oversubscription of a physical link, or due to a connection of higher priority or tighter service constraints getting the resource of the physical link.


In 1980 IBM showed up on Bill Gates' doorstep seeking an operating system for its upcoming personal computer. Mr. Gates did not have one. But he knew someone that had one. A little firm down the road (in Seattle) had developed QDOS ” the Quick and Dirty Operating System. It looked just right for IBM's PC. Mr. Gates bought QDOS for $100,000 and renamed it MS-DOS ” Microsoft Disk Operating System. According to the Economist Magazine of May 22, 1993, some jealous Microsoft rivals claim that MS-DOS now stands for Microsoft Seeks Domination Over Society.


Quantizing Distortion Units. ITU-T Recommendation G.113 defines one QDU as the amount of degradation introduced into a voice channel by a single conversion from analog to PCM and back to analog (analog-PCM-analog). Where several voice channels are connected in tandem, the end-to-end QDU rating for the whole circuit is calculated by adding the number of conversions from analog to PCM and back. For example: analog - PCM - analog - PCM - analog introduces 2QDUs.


Quantum Flow Control. A method of flow control for ATM proposed as an alternative to ER (Explicit Rate), the current rate-based flow control mechanism. QFC is proposed by the QFC Alliance, which consists of a group of vendors including Digital Equipment Corp., Thomson-CSF and Ascom Nexion. QFC is touted as the solution for flow control in long-haul ATM implementations where data traffic is supported in addition to widely varying levels of high-priority traffic such as voice, video and multimedia information. QFC provides assurances that the buffers in the destination switch will not overflow, which would require retransmissions of low priority data (i.e., data), while the higher-priority data (i.e., voice, video and multimedia) flows through the network without difficulty. QFC also establishes limits on the bandwidth available to any individual connection, thereby avoiding the potential for monopolization of the switch buffers. See also Flow Control. Compare with Rate-Based Flow Control and ER.


Qualified Logical Link Control. Software package that allows Systems Network Architecture (SNA) commands to be transmitted over an X.25 packet data network (PDN). See also NPSI. Contrast with DSP.


Queue Management System.


A UNIX-like realtime operating system that works really well for computer telephony applications. Trademark of QNX Software Systems Ltd. qnx.com


Query on Release. See LNP (Local Number Portability.)


Quality of Service. See Class of Service and Quality of Service.


Quadrature Phase Amplitude Modulation. Used in high speed modems to send multiple data bits per baud. This type of modulation views the electrical signal as a vector that can be placed, by combining the the signals of two amplitude modulators that are 90 degrees out of phase, on a matrix of targets (sometimes called an eye-pattern) representing numeric values. The number of bits / baud determines the number of targets that are required. It is used in a wide variety of modems from voice frequency up to microwave baseband (100 MHz - 800 Mhz).


Quaternary Phase Shift Keying. A compression technique used in modems and in wireless networks, such as CDMA (Code Division Multiple Access) and 802.11a. A simple implementation of QPSK allows the transmission of 2 bits per symbol, with each symbol being a phase range of the sine wave. In this fashion, a 2:1 compression ratio is achieved, resulting in a doubling of the efficiency with which a circuit is employed. For instance, 0- 90 degrees of phase indicates a 11 bit pattern; 90-180 degrees a 01; 180-270 a 10; and 270-360 a 00. In wireless networks, two carrier signals can be used, each of which is separated by 90 degrees of phase (position). If the phase of the carrier signals were not separated, one would be indistinguishable from the other. A 90-degree phase shift provides maximum phase separation and, therefore, maximum delineation between the carrier signals. See also 802.11a and CDMA.


Queued Packet Synchronous Exchange. Medium Access Control technology developed by the University of Western Australia for use in extending the reach of LANs across a Metropolitan Area Network (MAN). The technology was licensed to QPSX, Ltd. and subsequently was standardized by the IEEE as 802.6. QPSX was commercialized by Bellcore as DQDB, which is the access technology for SMDS networks. See also DQDB and SMDS.

QR Connector

See XLR connector.


Quasi-Random Sequence Signals or Quasi-Random Signal Source. An industry-standard test pattern employing a fixed bit sequence to simulate random data and used to Signals used for testing digital circuits, in particular DS-1 (i.e. T-1) circuits.


Quadrature Sideband Amplitude Modulation. A sophisticated modulation technique, using variations in signal amplitude, that allows data-encoded symbols to be represented as any of 16 or 32 different states. See also QAM and Sideband.


The name under which PSS1 (Private Signaling System number 1), an international standard established by the ISO (International Organization for Standardization) and the IEC (International Electrotechnical Commission). QSIG is a global signaling and control standard for PINX-to-PINX (Private Integrated Network eXchange) applications, intended for use in private corporate ISDN networks to link multiple vendors' PBXs while retaining feature transparency. "Q" comes from the fact that the standard is an extension of the "Q" logical reference point defined by the ITU-T in its Q.93x series of recommendations for generic functions and basic services of ISDN SIGnaling systems. The early work on QSIG was accomplished by the European Computer Manufacturers Association (ECMA), which built on ITU-T ISDN standards for public networks. As a result, and for obvious reasons, QSIG, therefore, builds on the ITU-T DSS1 (Digital Subscriber Signaling 1) standard. DSS1 defines the logical reference point for ISDN at the user equipment. The impetus for this effort was that of encouraging the harmonization of existing, proprietary private network "standards" toward the reduction of technical trade barriers in the pan-European market. Subsequently, the EC (European Commission) became involved, charging ETSI (European Telecommunications Standards Institute) with the responsibility for further development and promotion of the standard in collaboration with CENELEC (translated from French as European Electrotechnical Standards Committee). QSIG standards are submitted to the JTC1 (Joint Technical Committee 1), which is a collaboration of the ISO (International Standards Organization) and the IEC (International Electrotechnical Commission). The standards also are promoted by the IPNS (ISDN PBX Networking Specification) Forum, which comprises a number of manufacturing companies such as Alcatel, Ascom, Ericsson, Lucent, Nortel, Philips and Siemens.

QSIG is much like the public network DSS1 standard set by the ITU-T, at least at Layers 1 & 2 of the OSI Reference Model. Differences appear at Layer 3, the Network Layer, as QSIG is intended for use in private networks and is symmetrical in nature, with the user side and the network side being identical. Further, QSIG is designed for peer-to-peer operation, although the standard addresses transit node capabilities, as well. QSIG also addresses both connection-oriented and connectionless services, unlike DSS1 standards which address only the former. ECMA currently is working on B-QSIG, which will extend the QSIG protocol stack to B-ISDN (Broadband ISDN). According to the IPNS Forum, QSIG offers user benefits including vendor independence, guaranteed PBX interoperability, free-form network topology, support for an unlimited number of nodes, flexible numbering plan, flexibility of interconnecting transmission technologies (i.e., analog or digital leased lines, radio and satellite links, and public VPN services). Supplementary services offered by QSIG include name identification, call intrusion, do not disturb, path replacement, operator services, mobility services, and call completion on no reply. As a standards recommendation, QSIG provides manufacturers the freedom to develop custom features, with QSIG providing a standard mechanism for transporting such non-standard features. See also CENELEC, EC, ECMA, ETSI, IEC, ISO, and OSI Reference Model.


Quick Time Conference. Apple Computer's cross-platform, video-conferencing, collaborative computing and multimedia communications technology.


See Quicktime VR.


A slang term for cable conductor with four single, plastic coated wires not twisted together and contained in a single plastic covering. Quad wiring has been traditionally used inside houses and small offices. Since it will not handle data well, it is no longer being recommended for installation anywhere , except in single-line analog (never data) applications. In the old days, a quad wire would support two analog phone lines. Color coding in quad wire in North America is red-green, yellow-black. When I showed this definition to a professional installer, he told me that quad wire was generally not used anymore except by ignorant do-it-yourselfers, cheap telcos (telephone companies), irresponsible contractors, etc. See Quad Wire.

Quad Block

Where "quad" wiring is terminated inside a residence quad block is typically a four screw terminal mounting that has some type of modular plug.

Quad Cable

Cables where four wires are twisted as a unit. High crosstalk may be encountered among the wires within a quad unit.

Quad Fiber Cable

A cable consisting of four single optical fiber cables placed inside a polyvinyl chloride jacket with a rip cord to peel back the jacket and gain access to each single cable.

Quad Inside Wire

Quad IW. Older phone wire. It has four solid core copper conductors ” red, green, black, yellow. Line one colors are green and red, line two colors are yellow and black. Since it's often not twisted, it's susceptible to RFI.

Quad Lock Conduit

Conduit that's designed to be buried. The four conduits let companies lease space to each other in a way that's easy to track for fiber- optic cable installers /splicers, etc.

Quad Wire

A type of wire which contains four untwisted copper conductors in a plastic sheath. These four conductors are not two separate twisted pairs, although the four may have a very "slow" twist to them. Quad wiring is no longer recommended by the telephone industry for installation in other than analog single line applications. In short, quad is dead. See Quad.

Quad VGA

QXGA. A new standard for a display resolution, namely 2,048 x 1,536 pixels.

Quadded Cable

A cable in which at least some of the conductors are arranged in the form of a quad.


An antenna mounting system used for mounting an antenna on a sloped roof.

Quadrature Amplitude Modulation

See QAM.

Quadrature Sideband Amplitude Modulation



See Mated Pairs.


QUALification DIRective. A wireless term for changes to a VLR (Visitor Location Register), a database which contains information about legitimate roamers and which describes the features to which they have access. The response to the QUALDIR is a "qualdir" (lower case). See also VLR.

Quality Of Service

QoS. Quality of Service is a measure of the telecommunications ” voice, data and/or video ” service quality provided to a subscriber. It's not easy to define "quality" of voice telephone service. It's very subjective . Is the call easy to hear? Is it "clear?" Is it loud enough, etc.? The state Public Service Commissions (PSCs) have attempted to define the quality of service they want the residents of their states to have. And they have created various measures to which they insist phone companies conform. They tend to be more measurable. They include the longest time someone should wait after picking up the handset before they receive dial tone (three seconds in most states).

Quality of Service is more easy to define in digital circuits, since you can assign specific error conditions and compare them. For example if you were defining QoS with respect to ATM, it would be defined on an end-to-end basis in terms of the attributes of the end-toend ATM connection, as detailed in ITU-T Recommendation I.350. The ATM Forum extended this standard through the definition of QoS parameters and reference configurations for the User Network Interface (UNI). ATM Performance Parameters include the following:

  • Cell Error Ratio (CER)

  • Severely Errored Cell Block Ratio (SECBR)

  • Cell Loss Ratio (CLR)Cell Misinsertion Rate (CMR)

  • Cell Transfer Delay (CTD)

  • Mean Cell Transfer Delay (MCTD)

  • Cell Delay Variability (CDV)

ATM Quality of Service (QoS) objectives set by the carriers are defined as Class of Service 1, 2, 3, and 4. Here is an explanation of the various classes: Class 1: Equivalent to digital private lines. Class 2: Supports traffic such as audioconferencing, videoconferencing and multimedia Class 3: Addresses connection-oriented protocols such as SDLC and Frame Relay Class. 4: Supports connectionless data protocols such as SMDS.

In the middle 90s, the concept of carrying voice and video over IP (Internet Protocol) networks suddenly became very important. In a White Paper which Microsoft put out in September 1997, it discussed QoS with the following words:

"What is Quality of Service? In contrast to traditional data traffic, multimedia streams, such as those used in IP Telephony or videoconferencing, may be extremely bandwidth and delay sensitive, imposing unique quality of service (QoS) demands on the underlying networks that carry them. Unfortunately, IP, with a connectionless, "best-effort" delivery model, does not guarantee delivery of packets in order, in a timely manner, or at all. In order to deploy real-time applications over IP networks with an acceptable level of quality, certain bandwidth, latency, and jitter requirements must be guaranteed, and must be met in a fashion that allows multimedia traffic to coexist with traditional data traffic on the same network." For another explanation (this time from Cisco), go to Class of Service.

Qos is full of confusing and sometimes contradictory terms. Here's how Network computing of 9.4.2003 defines them:

Quality of Service: A way to provide better or stable service for select network traffic through bandwidth or latency control.

Saturation Point: The amount of load (packet count, simultaneous sessions or bandwidth utilization) that causes a network device to start dropping an unacceptable percentage packets.

Flow: A session between two hosts (such as a TCP session)> This includes handshaking, data transfer and termination. there can be multiple simultaneous flows between two hosts .

Class: A grouping of flows based on common criteria. May include protocol, source/destination address or subnet.

Classification: Detecting, identifying and potentially marking flows. Burst Rate vs. Maximum Rate: If a QoS device supports bursting, it can let a class or flow be configured to use more bandwidth than the maximum rate, but only if extra, unused bandwidth is available. Think of it as a second max rate: Burst will always be higher than max rate. If burst equals max rate, then bursting is effectively disabled.

Quantity Above Threshold Indicator

QAT. The sum of itemized call minutes that exceeds the minimum threshold of 1500 Minutes of Usage (MOU) that is eligible for a volume discount.

Quantity Type Indicator

A Verizon definition. A code that identifies the quantity type for local calling plan charges.


The converting of a native analog signal to digital format through a sampling and quantizing process. This process is accomplished in a CODEC and is necessary in order to send analog data (voice or video) over a digital network (e.g., T-carrier or ATM) or through a digital switch (e.g., PBX or central office).

In the case of a voice signal and using PCM (Pulse Code Modulation), for instance, the amplitude of the native analog signal is sampled 8,000 times per second, with the each sampled amplitude value being expressed as an 8-bit digital value (byte) consisting of a specific combination of ones and zeros. At the receiving end of the communication, the process is reversed , with the digital value being translated into an analog amplitude value. The result is an approximation of the original analog signal, as it was sampled rather than digitized exactly. Note that the original analog signal varied continuously in terms of both amplitude and frequency. Clearly, the higher the rate of sampling, the truer the reproduced approximate signal; the lower the rate of sampling, the less accurate the reproduced signal. In other words, a low rate of sampling would yield relatively unpleasant voice or fuzzy video as a result of what is known as "quantizing noise." However, a lower rate of sampling requires less bandwidth over the network or through the switch, yielding obvious cost benefits. As is that case with many things in life, there are tradeoffs between cost and quality.

Quantization Noise

Signal errors which result from the process of digitizing (and therefore ascribing finite quantities to) a continuously variable signal. See Quantization.


The process of encoding a PAM signal (Pulse Amplitude Signal) into a PCM signal (Pulse Code Modulation). See Quantization.


The second stage of pulse code modulation (PCM), for instance. The waveform samples obtained from each communication channel are measured to obtain a discrete value of amplitude. These quantized values are converted to a binary code and transmitted to a distant location to reconstruct an approximation of the original waveform. See Quantize and Quantization.

Quantizing Noise

Noise caused by the inability of an analog signal to be exactly replicated in digital form. Such noise is the result of the fact that the original signal was sampled, yielding an approximation (but not exact replica) of the original signal as it is reconstructed on the receiving end of the communication.


In physics, quantum means a very small indivisible piece of energy. This word is widely misused by people who refer to "a quantum leap," meaning a big leap. See Quantum Computing and Quantum Leap.

Quantum Computing

A developing computing technology that exploits the properties of atoms to create a radically different type of computer architecture through quantum physics. Quantum computing relies on the basic traits of an atom, such as the direction of its spin (i.e., left-to-right and right-to-left ), to create a state, such as a "1" or "0," much as conventional computers use variations in electrical energy (i.e., positive and negative polarity). Further, quantum computing theory suggests that intermediate states can be created. Further, the entanglement of spins between atoms can enable them to function as a collective whole. Qubits (quantum bits), therefore, are more than binary "1" and "0" bits. Qubits speak paragraphs, rather than bits of letters that make up words that make up sentences that make up paragraphs. This concept shatters the bounds of binary logic, linear processing, and computing speed. Don't look for it next week, or next month, or next year. Tell your grandchildren to look for it. Tell them to buy a copy of this book, which by then will be written by my grandchildren and will be in at least its 100th edition. But then, quantum publishing may have rendered the printed word to be obsolete, and they may be reading this book by watching atoms rotate. See Quantum and Quantum Leap.

Quantum Flow Control

An ATM term. See QFC.

Quantum Leap

In physics, quantum means a very small parcel or increment of energy. Also in physics, quantum leap or quantum jump refers to the abrupt transition (of something such as an electron , atom or molecule ) from one discrete energy state to another. In popular usage, the term refers to an abrupt change, dramatic advance, or sudden increase. For instance, it might be said that major system enhancements which entail "fork- lift upgrades" involve quantum leaps in cost. Systems which are scalable do not. See also Forklift Upgrade and Scalable.

Quantum Mirage Effect

This process uses quantum waves to transfer information from one part of a nanoprocessor to another without relying on any physical connections.


Physicist Murray Gell-Mann named the sub-atomic particles known as quarks for a random line in James Joyce, "Three quarks for Muster Mark!"

Quarter Speed

An international leased teletype line capable of transmitting one quarter of Telex speed of 16 2/3 words per minute.

Quarter Wave Antenna

An antenna, the length of which is 1/4 that of the wave length received.


Code-name for a tablet-like, quarter-VGA portrait screen size , pen-based, reference design, typically used in cell phones or PDAs. See also Quartz Crystal.

Quartz Crystal

A small piece of quartz which is cut to a precise size. When electricity is applied to the crystal, it vibrates at a specific and precise frequency. Quartz crystals are often used in watches . They vibrate quickly and make the watch far more accurate than a timing device which vibrates far more slowly, like a pendulum, for example, or a tick tock watch.

Quasi-Analog Signal

A reader berated me for not including a definition for quasi- analog. I found this definition on the Internet. It's really stupid. It defines a quasi-analog signal "as a digital signal that has been converted to a form suitable for transmission over a specified analog channel. Note: The specification of the analog channel should include frequency range, bandwidth, signal-to-noise ratio, and envelope delay distortion. When quasi-analog form of signaling is used to convey message traffic over dial-up telephone systems, it is often referred to as voice-data. A modem may be used for the conversion process." Seems to my tiny brain that it's a digital signal (like from a computer) before it's converted into an analog signal for transmission over an analog phone line. So it's not really a quasi-anything. It's either one or the other. See Analog and Digital.

Quasi-Random Signal

QR. A pseudo random test signal that has artificial constraints to limit the maximum number of zeros in the bit sequence.


Quantum Bit. See Quantum Computing.

Quenched Gap

A spark gap so arranged that the spark is quenched quickly by a cooling effect. A method used to give impulse excitation . An old radio term.


  1. In data communications, it's the process by which a master station (or mainframe or boss computer) asks a slave station to identify itself and tell its status, i.e. is it busy, alive , OK, waiting, etc.?

  2. In database, a query is a request for the retrieval of data.

Query Indicator

An indication to subsequent nodes in the call path that a Local Number Portability (LNP) query has been performed. The industry has allotted the M bit within the Forward Call Indicator (FCI) for this purpose.

Query Language

A programming language designed to make it easier to specify what information a user wants to retrieve from a database.

Query Optimization

New database technology for optimiziing performance, minimizing administration and querying distributed, heterogeneous information. In short, a fancy term for the same old thing. Soon there'll be high-priced consultants in this field.


A stream of tasks waiting to be executed, or a series of calls, messages, or packets awaiting the availability of a network resource. For example, the calls, messages or packets may be awaiting the availability of a circuit, or the availability of the computational resources of a switch or router in order that they might be processed and sent on their way. The messages or packets may be held in a buffer (i.e., temporary memory) until such time as the network resource is available. A queue commonly is associated with a buffer on an incoming port. Queues and associated buffers also may be associated with outgoing ports, or may even be internal to a complex switching matrix. See Queuing.

Queue Management

In a network, tasks like retrieval and writes to a jukebox come randomly from all the users. These tasks vary in urgency ” retrievals are higher priority than writes, for example. Queue management sorts out requests from the network by priority. Queue management also enhances the performance of a jukebox, by intelligently reordering requests. For example, if there are three requests for images on platter 1 and two from platter 2 and the another from platter 1, queue management means the requests from platter 1 will get handled together, then go to platter two. Sometimes it's called "elevator sorting" ” responding to requests in logical order, not in the order in which they were made.

Queue Service Interval

The maximum length of time a queue will go unsampled.

Queued Arbitrated

QA. A type of SMDS time slot which supports asynchronous data traffic. As such data is not time-sensitive, it is acceptable for the data transmission to take place over time slots on an "as available" basis.

Queued Call

A call that is waiting in a queue of telephone calls to be serviced by a system resource is a queued call. An ACD group is an example.

Queued Mode

Calls entering an Automatic Call Distributing system wait in a queue are presented, one at a time, to the first idle trunk in the chosen group.

Queued Packet Synchronous Exchange


Queued Telecommunications Access Method

QTAM. A program component in a computer which handles some of the communications processing tasks for an application program. QTAM is employed in data collection, message switching and many other teleprocessing applications.


The act of "stacking" or holding calls to be handled by a specific person, trunk or trunk group. There are two reasons to queue telephone calls:

  1. Because you simply don't have enough trunks.

  2. Because you want to save money.

You can queue calls mechanically using your telephone switch or manually using a human operator or attendant. There are two ways you can queue calls ” hold-on or call- back. In "hold-on" queuing, you dial, you get some queuing tone (or the operator tells you you're being queued), then you wait on-line until a line becomes free and you're connected. In "call-back" queuing, you tell the operator or the machine you want to dial a call. And you hang up. When the line becomes free you are called back and connected. There are advantages and disadvantages to both systems. In "hold-on" queuing, you waste your time but save on phone time. In call-back queuing, you waste less of your time, but more phone line time. In call-back queuing, the operator or the phone system has to grab the line you want and simultaneously call you. By then, you may have left your desk. The call may be wasted , etc. The line given to you could have been used by someone else, etc. Queuing calls as a method to save money on long distance calling makes sense ONLY:

  1. IF you are out of trunks because of a temporary surge in telephone traffic ” perhaps at your peak, peak busy time and it's very expensive to buy sufficient "cheap long distance" trunks to handle every conceivable peak, and

  2. IF you never plan on having a queue longer than 20 seconds for a hold-on queue and 60 seconds for a call-back queue and

  3. IF you are queuing calls into an expensive fixed-cost line. For example a tie line between New York and London. If you queue calls into a variable cost line, like an interstate WATS line, you will save money over throwing the call onto DDD, but the pennies you save usually won't be worth it ” considering the aggravation you're going to cause your people. Queuing is a very sensitive subject in corporate telecommunications departments. People don't like to wait for telephone lines. They consider that insulting to them personally , damaging to their "productivity" and to heck with the cost. Queues do, however, make enormous sense. Even a queue as short as ten seconds can save big amounts of money. Queues of a maximum length of ten seconds are rarely noticed. These days some of the more modern PBXs will allow you to offer "selective" queuing, or levels of queuing. Upper management doesn't have to queue for the cheap long distance lines before it's bounced to the expensive ones. While lower management has to wait up to 30 seconds. And the worker bees (non-management) have to wait even longer. Queuing is also used on incoming trunks. See ACD and Queuing Theory.

Queueing Delay

Also spelled Queuing Delay. The length of time a data packet is held in queue in a buffer (i.e., temporary memory) while awaiting either processing by a device (e.g., switch or router) on the inbound side, or availability of a circuit on the outbound side. Queueing delay is one element of overall propagation delay, which is the total time required for a signal to transit a complete circuit, from transmitting device to receiving device. A circuit commonly comprises many links and many devices, each of which imposes some level of delay. See also Propagation Delay.

Queuing Theory

The study of the behavior of a system that uses queuing, such as a telephone system. Much of queuing theory derives from the science of Operations Research (OR). Dr. Leonard Kleinrock has written the authoritative books on the subject. He is probably a genius. His books are very difficult to understand for laymen. Here is an explanation of Queuing Theory from James Henry Green's Dow Jones-Irwin Handbook of Telecommunications (you can buy a copy from www.amazon.com or www. barnesandnoble .com):

"The most common (telephone) network design method involves modeling the (phone) network according to principles of queuing theory, which describes how customers or users behave in a queue. Three variables are considered in network design. The first is the arrival or input process that describes the way users array themselves as they arrive to request service...The second variable is the service process, which describes the way users are handled when they are taken from queue and admitted into the service providing mechanism. The third method is the queue discipline, which describes the way users behave when they encounter blockage in the network...Three reactions to blockage are possible:

  • Blocked calls held (BCH). When users encounter blockage, they immediately redial and reenter the queue.

  • Blocked calls cleared (BCC). When users encounter blockage, they wait for some time before redialing.

  • Blocked calls delayed (BCD). When users encounter blockage, they are placed in a holding circuit until capacity to serve them is available. See QUEUE. "Traffic engineers have different formulas or tables to apply, corresponding to the assumption about how users behave when they encounter blockage." See Poisson.

After I wrote the above definition, Lee Goeller, a noted traffic engineering expert contributed the following definition:

The study of systems in which customers wait in line for servers to become available, the "blocked calls delayed" condition in telephony (see TRAFFIC ENGINEERING). Although seldom used in designing voice networks (other techniques are usually more cost-effective ), queuing is very important in the design of packet networks where speed of transmission more than offsets the delay of waiting for a transmission facility to become available, and in staffing Automatic Call Distributors.


Quad Integrated Communications Controller.

Quick Clip

An electrical contact used to provide an insulation displacement connection to telecommunications cables.


See V.92.


Programming routines that allow an Apple Macintosh computer to display graphics on a screen. QuickDraw is also used for outputting text and images to printers not compatible with PostScript.


Mercury, an extremely poisonous chemical. Actually it's not a chemical. It's an element. See "mad as a hatter."


A dynamic-data format developed by Apple to be used for animation. QuickTime files can be used in documents created by other applications. For instance, a QuickTime video clip can be pasted into a word-processing document. QuickTime VR is the new Apple standard for Virtual Reality. See QuickTime VR.

QuickTime VR

QuickTime VR (QTVR) is the acknowledged standard for creating and viewing photo-realistic environments (panoramas) and real-world objects on Mac OS and Windows computers. Users interact with QuickTime VR content with a complete 360 degree perspective and control their viewpoint through the mouse, keyboard, trackpad or trackball . Using a QTVR-enabled authoring tool, panoramas and objects are automatically 'stitched together' from digitized photographs or 3D renderings to create a realistic visual perspective. The effect is awesome . As I wrote this, over 5,000 web sites were QuickTime enabled. One site I particularly enjoyed showed a hotel room. As a you moved your cursor, it seemed as though I was turning to see all 360 degrees of the hotel room. For more info http://quicktimevr.apple.com.

Quick Connect Block

Also called a 66-block or punch-down block. It's a 18" piece of metal and plastic which allows you to connect telephone wiring coming from two remote points. The quick-connect block has multiple metal "jaws" ranging horizontally and vertically. To connect up, you "punch" (or push) a wire between the two metal teeth of the "jaws." This both holds it firm and strips the wire's insulation, thus allowing for a good electrical connection. (There are special "punch-down" tools for punching wires into 66- blocks.) On a 66-block, one horizontal row of "jaws" is always the same conductor. To connect other wires to it, you simply punch those wires down along the row. Some 66- blocks have a gap between one side of the 66-block and the other. To connect one wire on one side to the wire on the other side, you have to use a BRIDGING CLIP. This is a small metal clip about one inch long. The bridging clip has one purpose: you can slip it off easily and thus cut one side of the circuit from the other. For example, if you connected central office trunks on one side of the 66-block and a PBX on the other, by removing the bridging clips, you can tell instantly if the trouble is in the PBX or in the central office. Two conductors on a 66-block makes a circuit ” a trunk or a line. Therefore, the trunk 212- 691-8215 (our main number) takes up the first two horizontal rows on our 66-block. The second two horizontal rows are taken up with 212-691-8216, and so on.

It is good to learn where your main 66-block is ” the one that connects you to the telephone company's central office lines. The 66-block is what the telephone company calls the " demarcation point." And they (the phone company) usually install the 66-block. On one side (the trunk side) of their block, they're responsible. On the other (the PBX, key system or phone side), you're responsible. By knowing how to test your lines at this point, you can know whose fault it is ” the phone company's or your equipment's. This can avoid having to wait until the phone company arrives, discovers it's not their problem and then sends you a hefty bill. Or the interconnect company arrives, finds out it's not their problem, and sends you a hefty bill, etc.

Quick Connect Blocks or 66-blocks are found in the Main Distribution Frame ” where lines coming out of the PBX are connected to the individual wires going to the phones, or to big cables going to clumps of phones in other parts of the building. They're also found in Satellite Distribution Frames where they take big cable coming in from the main distribution frame and connect it to the individual cable pairs going to the individual phones. See Connecting Block.

Quick Format

A DOS program which deletes the file allocation table and root directory of a disk but does not scan the disk for bad areas.

Quick Plug

A device which adapts a standard four wire telephone cord into a modular connector.


Apple Computer's video environment (like Microsoft's Video For Windows). Quicktime video files must be converted to *.AVI format to run under Microsoft's Video For Windows. Indeo video technology is supported under MacOS.


A quidnunc is a person who is eager to know the latest news and gossip, in short a busybody.


A fancy word for quiet. No noise. No activity. Quiescent time is the best time to write this dictionary. Sadly, it wasn't always to be.


A graphics term. An anti-aliasing technique, developed by nVidia, which uses a sampling pattern that looks like the five side of a die. This dot patter is called a quincunx.


This term is not an acronym. This public domain X.500 directory service, developed by University College London, demonstrates X.500 feasibility on TCP/IP (Transfer Control Protocol/Internet Protocol). This pioneering software package was developed to study the OSI (Open Systems Interconnections) Directory and provide extensive pilot capabilities. ISSUE (International Organization for Standardization Development Environment) provides commercial version of this software.


A family of teleconferencing products linked in a system designed to meet a customer's teleconferencing needs.


A standard of sorts for displays of 320x240 pixels. The more common VGA is 640x480 color pixels.


The name for a computer or typewriter keyboard. It got its name from the left side, top row of letter keys which spell QWERTY. One theory for the strange design of the QWERTY keyboard has to do with typewriter keyboards which had long metal arms that physically hit the paper. To keep the arms from jamming, they designed the QWERTY keyboard which split commonly used letters ” i.e. a, i, o, e ” to opposite sides of the keyboard. For years , people have argued that a keyboard called the Dvorak would be a much faster and more efficient. However, the U.S. General Service Administration in the 1950s contradicted the claims made by advocates of the Dvorak keyboard. The chief advocate was the patent owner, August Dvorak. According to September, 1995 Upside Magazine, his "book on the relative merits of QWERTY versus his own keyboard has about as much objectivity as a modern infomercial found on late night TV." With computers, there is no such thing as a "standard" QWERTY keyboard. Computer keyboards typically have 20 to 30 more keys than "standard" typewriter keyboards. Many of the keys are unique ” on some keyboards, not on others. Many of the keys on computer keyboards are called "function" keys. If you hit one of them, they might perform a complete function on the computer, e.g. save a file, move to the end of the file, etc. There is absolutely no such thing as a standard computer keyboard.


Qwest Communications International Inc. is a broadband communications carrier that went public with an IPO (Initial Public Offering) in 1997. Qwest built a substantial fiber network in North America and Europe, with the European network taking the form of the KPNQwest joint venture. On June 30, 2000, Qwest announced the completion of its merger with (read acquisition of) US West. US West was one of the seven Regional Holding Companies (RHCs) formed by the divestiture of the Bell Operating Companies (BOCs) by AT&T in 1984. See also US West.


Quad VGA. A new standard for a display resolution, namely 2,048 x 1,536 pixels.


Special billing arrangement provided by your local telephone company. Before there was automatic call accounting and before there was Centrex, the phone company would give you "time and charges" on every outgoing call. This service was called "QZ" billing. It was used by engineers, lawyers , accountants , consultants and other service people who had to bill their calls back to their clients .

Newton[ap]s Telecom Dictionary
Newton[ap]s Telecom Dictionary
ISBN: 979387345
Year: 2004
Pages: 133

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