O: O-Oxymoron

O-Off/On Hook


Used on switches to mean "OFF." The "ON" setting is "I."

O Band

The optical band, or window, specified by the ITU-T at a wavelength range between 1260nm and 1310nm (nanometers) for fiber optic transmission systems.

O Carrier

N-Carrier and O-Carrier ” Frequency division multiplexed analog carrier over long haul copper .


See O Band.


Operations and Maintenance.


Original Equipment Manufacturer. See OEM.


Optic to Electric conversion.


Short for Originator/Recipient in the X.400 MHS (Message Handling System).

O/R Name

A ITU (International Telegraph and Telephone Consultative Committee) term for the set of user attributes that identifies a specific MHS (Message Handling System) user . Example components are: given name, surname , ADMD (ADministrative Management Domain), country and PRMD (PRivate Management Domain), country and PRMD (PRivate Management Domain). An example of a complete O/R Address is: G=HARRY; S=NEWTON; I=HN; A=MARK400; O=PIPELINE; OUI=COMPUTER TELEPHONY; C=US.


  1. Office Automation. Nobody knows what it means. But there are many consultants out there who will tell you for the right amount of money. Actually, the early "office automation" seemed to translate into word processing for the masses. When someone discovered that word processing didn't enhance office productivity, office automation fell into disrepute.

  2. Operating Agency. An ITU (International Telecommunications Union) term. Any individual, company, corporation or governmental agency which operates a telecommunication installation intended for an international telecommunication service or capable of causing harmful interference with such a service. See also ROA.


Operations, Administration and Maintenance. See OAM.


Off Air Call Set Up. A wireless telecommunications term. A method of establishing a call to a mobile telephone where the radio channel is set up at the last possible moment.


Optical Add/Drop Multiplexer. Another term for ADM, which is a SONET term. See ADM and SONET.


Open Application Interface. Basically one or many openings in a telephone system that lets you link a computer to that phone system and lets the computer command the phone system to answer, delay, switch, hold etc. calls. The term is also called PHI ” as in PBX-Host-Interface. The term OAI was first used by PBX makers , NEC and InteCom. And now the term has become somewhat generic. Essentially every manufacturer of phone systems is evolving towards open application interfaces of their own. Many of these open interfaces are TSAPI-compatible and increasingly most are TAPI-compatible. See TAPI and TSAPI. According to Probe Research, there are really two separate "markets" for OAI or PHI:

First, there's Horizontal/Office Automation applications. These are applications that support business functions across organizational groups or industry verticals in inter- or intra- department business settings. Examples include voice mail, electronic mail, message centers, corporate telephone directories, automated screen-based dialing, personal productivity tools, conferencing, PBX feature enhancements, ANI interfaces, time clocks, 911 emergency service and compound image (data, text, image and voice) processing. I see these applications as all those useful, productivity-enhancing things I always wished my telephone systems would do if only they would let me program the thing. (Until OAI, all phone systems were totally closed architecture.)

Second, there's transaction applications. These are applications that support an actual business transaction ” customer service, inbound telephone order taking, outbound tele- marketing, market research, data gathering, inventory inquiry, account time billing, credit collections, locator services with or without transfer to the local dealer . These always require access to a computer database. These applications are generally complicated, time- sensitive and customized for each installation.

A sample OAI arrangement: In early 1993, Novell and AT&T inked a deal to put telephony onto Novell LANs. The Telephony Server NetWare Loadable Module (NLM) will be the first product. It is an AT&T PC-card sitting in the Novell File server. The card connects to the ASAI (Adjunct Switch Applications Interface) port on the AT&T Definity PBX. Anyone with a PC on the network and an AT&T phone on their desk can use telephone features, such as auto-dialing, conference calling and message management (a new term for integrating voice, fax and e-mail on your desktop PC via your LAN). The Novell/AT&T deal intends to create open Application Programming Interfaces (APIs) that third party developers can work with. A Novell/AT&T example of what could be developed: A user could select names from a directory on his PC. He could tell the Definity PBX through the PC over the LAN to place a conference call to those names. At the same time, a program running under NetWare would automatically send an e-mail to the people, alerting them to the conference call and giving them the agenda. All participants would have access to both the document and the conference call simultaneously . Here are some of the names which manufacturers of PBXs and computers have coined for their open application interfaces, also called PHIs:

ACL ” Applications Connectivity Link ” Siemens' protocol

ACT ” Applied Computer Telephony ” Hewlett Packard's generic application interface to PBXs

Application Bridge ” Aspect Telecommunications' ACD to host computer link

ASAI ” Lucent's Adjunct Switch Application Interface

CAM ” Tandem's Call Applications Manager ” the name of the Tandem software interface which provides the link between a call center switch telephone switch (either a PBX or an ACD) and all Tandem NonStop (fault tolerant) computers.

CIT ” Digital Equipment Corporation's Computer Integrated Telephony (works with major PBXs)

CSA ” Callpath Services Architecture ” IBM's Computer to PBX link

Call Frame ” Harris' PBX to computer link

Callbridge ” Rolm's CBX and Siemens to IBM host or non-IBM host computer link

Callpath ” IBM's announced, CICS application link to IBM's CSA, available on the AS400 in April of 1991

Callpath Host ” IBM and ROLM's CICS-based integrated voice and data applications platform which links to ROLM's 9751 PBX

CompuCall ” Northern Telecom's DMS central office link to computer interface

CPI ” Computer to PBX Interface developed by Northern Telecom and DEC

CSTA ” Computer Supported Telephony Application, RSL standard from ECMA

DECags ” DEC ASAI Gateway Services. Two-directional link to AT&T's Definity

DMI ” AT&T's Digital Multiplexed Interface, a T-1 PBX to computer interface

HCI ” Host Command Interface. Mitel's digital PBX link to DEC computer

IG ” AT&T's ISDN Gateway (one direction from the switch to the host)

ITG ” AT&T's Integrated Telemarketing Gateway (two directional)

ISDN/AP ” Northern Telecom's host to SL1 PBX protocol, which supports NT's Meridian Link

Meridian Link ” Northern Telecom's host to PBX link available on the Meridian PBX

ONA ” Open Network Architecture (for telephone central offices)

PACT ” Siemens' PBX and Computer Teaming, protocols between Siemens PBXs and computers

PDI ” Telenova/Lexar's Predictive Dialing Interface

PHI ” PBX Host Interface (a generic term coined by Probe Research)

SAI ” Stratus Computer Switch Application Interface

SCAI ” Switch to Computer Application Interface, one name given by Northern Telecom to PHI

SCIL ” Aristacom's Switch Computer Interface Link Transaction Link

Solid State Applications Interface Bridge ” Solid's State's PBX to external computer link.

STEP ” Speech and Telephony Environment for Programmers; WANG's link

Transaction Link ” Rockwell's link from its Galaxy ACD to an external computer

Teleos IRX-9000 ” Teleos' Intelligent Call Distribution platform

VoiceFrame ” Harris Digital Telephone Systems Division Platform


A key determination protocol, which defines a method for establishing security keys for use on a session basis by Internet hosts and routers. Oakley often is used in conjunction with ISAKMP (Internet Security Association and Key Management Protocol), a protocol that provides a method for authentication of communications between peers over the Internet. ISAKMP provides a framework for the management of security keys, and support for the negotiation of security attributes between associated peers. See also ISAKMP.


Operations, Administration and Maintenance. This usually term refers to the specifics of managing a system or network. It is typically a group of network management functions that provide network fault indication, performance information, and data and diagnosis functions. Some switches have computers devoted to OAM.


Operation, Administration, Maintenance and Provisioning.


Object Exchange: a set of high-level protocols allowing objects such as vCard contact information and vCalendar schedule entries to be exchanged using either IrDA (IrOBEX) or Bluetooth. Symbian OS implements IrOBEX for exchange of vCards, for example between a Nokia 9210 Communicator and an Ericsson R380 Smartphone and vCalendar.


Ordering and Billing Forum. A forum of the Carrier Liaison Committee (CLC) of ATIS (Alliance for Telecommunications Industry Solutions), originally called the Exchange Carriers Standards Association (ECSA). ATIS is heavily involved in standards issues including interconnection and interoperability. According to ATIS, the OBF "provides a forum for telecommunications customers and providers to identify, discuss and resolve national issues which affect ordering, billing, provisioning and exchange of information about access services, other connectivity and related matters." The six standing committees of the OBF are heavily involved in the development of standard mechanisms by which CLECs (Competitive Local Exchange Carriers) and ILECs (Incumbent LECs) can interface effectively; such interface is required in the competitive environment fostered by the Telecommunications Act of 1996, and by various state initiatives. See also ATIS, CLEC and ILEC. www.atis.org.


Open Buying on the Internet. A standard which provides a generic set of requirements, an architecture, and a technical specification for Internet purchasing solutions in the general context of Electronic Commerce. The OBI standard was developed by the OBI Consortium; membership is open to buying and selling organizations, technology companies, financial institutions, and other interested parties. See also Electronic Commerce. www.supplyworks.com/obi.


  1. In the context of network management, an object is a numeric value that represents some aspect of a managed device. An object identifier is a sequence of numbers separated by periods, which uniquely defines the object within a MIB. See MIB.

  2. In its simplest form in computing, an object is a unit of information. It can be used much more broadly, depending on the application. In X.400, an object contains both attributes and method describing how the content is to be interpreted and/or operated on.

  3. In object-oriented programming, a variable comprising both routines and data that is treated as a discrete entity. An object is based on a specific model, where a client using an object's services gains access to the object's data through an interface consisting of a set of methods or related functions. The client can then call these methods to perform operations.

  4. An entity or component, identifiable by the user, that may be distinguished by its properties, operations, and relationships.

See also Object Oriented Programming.

Object Cache Scavenger

The code that periodically scans the cache for objects to be discarded. It deletes from the cache files that have not been used recently and therefore are unlikely to be used again in the near future.

Object Code

A term usually applied to the executable, machine-readable, form of a software program. Object code is instruction code in machine language produced as the output of a compiler or a assembler. The original program, or code, is called the source Code. The term is also used to refer to an intermediate state of compilation, which is different from the initial source code and the final binary object code. See Source Code.

Object Definition Alliance

A group formed to establish software standards for interactive multimedia applications that will operate uniformly over a variety of hardware, operating systems and networks.

Object Encapsulation

Data and procedures may be encapsulated to produce a single object, thereby hiding complexity.

Object Handle

Code that includes access control information and a pointer to the object itself.

Object Inheritance

The transfer of characteristics down a hierarchy from one to another.

Object Linking And Embedding

OLE. An enhancement to DDE protocol that allows you to embed or link data created in one Windows application in a document created in another application, and subsequently edit that data in the original application without leaving the compound document. See DDE and OLE.

Object Orientation

Representing the latest approach to accurately model the real world in computer applications, object orientation is an umbrella concept used to describe a suite of technologies that enable software products that are highly modular and reusable. Applications, data, networks, and computing systems are treated as objects that can be mixed and matched flexibly rather than as components of a system with built-in relationships. As a result, an application need not be tied to a specific system or data to a specific application. The four central object-oriented concepts are encapsulation, message passing, inheritance, and late binding. This definition courtesy Microsoft.

Object Oriented File System

A file system, based on object-oriented programming, that allows permanent storage of objects and associated links.

Object Oriented Programming

OOP. Object oriented programming is a form of software development that models the real world through representation of "objects" or modules that contain data as well as instructions that work upon that data. These objects are the encapsulation of the attributes, relationships, and methods of software-identifiable program components. Object-oriented methodology differs from conventional software programming where functions contained in code are found within an application. Although hype about object-oriented technology is fairly recent, the approach was first introduced in the programming language Simula developed in Norway in the late 1960s. The methodology was based on the way children learn (i.e., object + action = result). The idea of object oriented programming is make the writing of complex computer software much easier. The idea is to simply combine objects together to produce a fully- written software application. The work, goes into producing all the objects. They are the building blocks. Theoretically, libraries of objects will be worth a fortune to those companies who develop them.

Object oriented programming is not easy to understand. Here's a definition of object- oriented programming from Business Week, September 30, 1991. "Software objects are chunks of programming and data that can behave like things in the real world. An object can be a business form, an insurance policy or even an automobile axle. The axle object would include data describing its physical dimensions and programming that describes how it interacts with other parts , such as wheels and struts. A system for a human resources department would have objects called employees , which would have data about each worker and the programming needed to calculate salary raises and vacation pay, sign up dependents for benefits, and make payroll deductions. Because objects have 'intelligence,' they know what they are and what they can and can't do. Thus objects can automatically carry out tasks such as calling into another computer, perhaps to update a file when an employee is promoted. The biggest advantage of objects is they can be reused in different programs. The object in an electronic-mail program that places messages in alphabetical order can also be used to alphabetize invoices. Thus, programs can be built from prefabricated, pretested building blocks in a fraction of the time it would take to build them from scratch. Programs can be upgraded by simply adding new objects."

The key concepts of object-oriented programming, according to ComputerWorld are

  1. OBJECTS. The basic building block of a program is an object. Objects are software entities. They may model something physical like a person, or they may model something virtual like a checking account. Normally an object has one or more attributes (fields) that collectively define the state of the object; behavior defined by a set of methods (procedures) that can modify those attributes; and an identity that distinguishes it from all other objects. Some objects may be transient, existing temporarily during the execution of a program, i.e., only during run time. Others may be persistent, existing on some form of permanent storage (file, database, programming library) after the program finishes.

  2. ENCAPSULATION. This concept refers to the hiding of most of the details of the object. Both the attributes (data structure) and the methods (procedures) are hidden. Associated with the object is a set of operations it can perform. These are not hidden. They constitute a well-defined interface ” that aspect of the object that is externally visible. The point of encapsulation is to isolate the internal workings of the object so that, if they must be modified, those changes will also be isolated and not affect any part of the program.

  3. MESSAGING. One object requests another object to perform its operation through messaging. The client object sends a message to the server object consisting of the identity of the server object, the name of the operation and, in some cases, optional parameters. The names of the operations are limited to those defined for that object. For example, the operations for a checking account object may be defined to be OPEN, DEBIT, CREDIT, COMPUTE INTEREST, ISSUE STATEMENT, SCHEDULE AUDIT, AND CLOSE.

  4. DATA ABSTRACTION. An object is sometimes referred to as an instance of an abstract data type or class. Abstract data types are constructed using the built-in data types supported by the underlying programming language, such as integer and date. The common characteristics (both attributes and methods) of a group of similar objects are collected to create a new data type or class. Not only is this a natural way to think about the problem domain, it is a very efficient way to write programs. Instead of individually describing several dozen instances, the programmer describes the class once. Once identified, each instance is complete with the exception of its instance variables. The instance variables are associated with each instance, i.e., each object; methods exist only with the classes.

  5. INHERITANCE. Data abstraction can be carried up several levels. Classes can have super-classes and subclasses. In moving to a level of greater specificity, the application developer has the option to retain some attributes and methods of the super-class, while dropping or adding new attributes or methods. This allows greater flexibility in class definition. It is even possible in some languages to inherit from more than one parent. This is referred to as multiple inheritance.

Objective Percent Fill ” Lines

A telephone company term. The objective percent line fill provides for line equipments that are administratively unusable because of their use for test, assignment restrictions such as class-of-service, and for being out on assignment lists. This percent which is a percent of the total line equipment installed less those required for trunks will vary according to the entity equipment type and its service features. The objective percent line fill should not be one value applied to all entities, but is derived for each individual entity on an empirical basis by the Network Administrator. Local OTC policy may dictate specific values to be used with each type of switching system and the procedures to be followed when changing these values. See also Objective Percent Fill ” Numbers.

Objective Percent Fill ” Numbers

A telephone company term. The objective percent number fill provides for numbers that are administratively unusable because of intercept requirements, PBX growth coin and official series, rate protection, and for other requirements such as being out on assignment lists. Care also needs to be taken, where applicable , to make allowance for CENTREX-CO and CENTREX-CU requirements. As in percent line fill, the quantity of numbers classified as administratively unusable will vary with an entity's characteristics. The objective percent number fill which is a percent of the total numbers installed less those required for trunks is derived on an empirical basis for each individual entity by the Network Administrator. Local OTC policy may dictate specific values to be used with each type of switching system and the procedures to be followed when changing these values. See also Objective Percent Fill ” Lines.

Object Request Broker

ORB. An object-oriented system consisting of middle- ware which manages message traffic between application software and computer/soft- ware platforms. As an application sends a message to an object, it need only identify the object by name. The ORB keeps track of the actual addresses of all such objects and, therefore, is able to route the request to the specific address space where the object resides in the system. CORBA (Common Object Request Broker Architecture), developed as an ORB standard by the OMG (Object Management Group), provides a standard interface for inter- operability between object management systems residing on disparate platforms. SEE CORBA and OMG.


Op rateur de Boucle Locale (Local Loop Operator) in France.


In light of the news of the so called human cloning going on, we have to ask ourselves the hypothetical question: If you pushed your naked clone off the top of a tall building, would it be:

  1. murder,

  2. suicide, or

  3. merely making an obscene clone fall.


The Supreme Court of the United States has defined obscenity as speech lacking in any social value. The Court has said that obscenity is entitled for First Amendment protection. But it may be regulated to a greater or less degree, depending on the medium ” TV yes, paper no. Indecency on the Internet is under the jurisdiction of the Communications Decency Act of 1996.

Obstruction Lights

Warning lights mounted on the side of an antenna tower.


  1. Operator Centralization.

  2. Optical Carrier. A SONET optical signal. See OC-1.


Optical Carrier-level 1. OC-1 is 51.840 million bits per second. The optical counterpart of STS-1 (Synchronous Transport Signal-1), which is the fundamental signaling rate of 51.840 Mbps on which the SONET (Synchronous Optical NETwork) hierarchy is based. OC-1 provides for the direct electrical-to-optical mapping of the STS-1 signal with frame synchronous scrambling . The STS-1 signal originates as a DS-3 (T-3) electrical signal, which operates at a raw signaling rate of 44.736 Mbps and which supports 672 voice-grade digital channels of 64 Kbps; the additional bps are attributable to optical processing overhead (signaling and control data). All higher levels are direct multiples of OC-1 (e.g., OC-3 equals three times OC-1). See also Concatenation, OC-3, OC-12, OC-48, OC-192 and OC-256.


Optical Carrier-level 3. A SONET channel equal to three DS-3s, which is equal to 155.52 Mbps. See also Concatenation, OC-1, OC-3c, and SONET.


Optical Carrier-level 3 concatenated . An OC-3 signal comprising three OC-1s which are linked together to form a contiguous chunk of bandwidth of 155.52 Mbps. The first OC-1 in the OC-3c data stream identifies this concatenation so that all other devices which act on the signal subsequently can quickly and easily multiplex , switch, transport and deliver the OC-3 data stream as a single entity. Further, concatenation improves SONET efficiency, as only the first OC-1 frame in the OC-3 data stream carries the full SONET overhead (i.e., signaling and control data). Each of the subsequent two SONET frames in the OC-3c signal are relieved of Path Overhead (POH) of nine bytes (i.e., 72 bits). That fact frees up 576 Kbps of bandwidth for data payload in each of the subsequent two frames, as each OC-1 frame is sent 8,000 times per second. See also Concatenation, OC-1, OC-3, and SONET.


Optical Carrier-level 12. SONET channel of 622.08 Mbps. See also Concatenation, OC-1, OC-12c, OC-N and SONET.


Optical Carrier-level 12 concatenated. An OC-12 signal comprising 12 OC-1s which are linked together to form a contiguous chunk of bandwidth of 622.08 Mbps. The first OC-1 in the OC-12c data stream identifies this concatenation so that all other devices which act on the signal subsequently can quickly and easily multiplex, switch, transport and deliver the OC-12 data stream as a single entity. Further, concatenation improves SONET efficiency, as only the first OC-1 frame in the OC-12c data stream carries the full SONET overhead (i.e., signaling and control data). Each of the subsequent SONET frames in the OC-12c signal are relieved of Path Overhead (POH) of nine bytes (i.e., 72 bits). That fact frees up 576 Kbps of bandwidth for data payload for each of the subsequent 11 frames, as each OC-1 frame is sent 8,000 times per second. See also Concatenation, OC-1, OC-12, and SONET.


Optical Carrier-level 48. SONET channel of 2.488 Gbps. How you calculate OC- 48 is to multiply 51.84 Mbps by 48. That gives you 2.488 thousand million bits per second, or roughly 2.5 Gbps (Gigabit per second). See also Concatenation, OC-1, OC-N and SONET.


OC-48c is 0C-48 concatenated. See OC-48 and Concatenation.


Optical Carrier level 192. SONET channel of 9.953 thousand million bits per second (Gbps). How you calculate the capacity of an OC-192 is to multiply times 192 by 51.840 million bits per second and thus you get 9.953 thousand million bits per second ” gigabits per second. See OC-1, OC-N and SONET.


Optical Carrier-level 256. The digital bit rate of OC-256 is 13.271.04 thousand million (Gbps) bits per second, which will accommodate 172,032 voice circuits, which is equivalent to 7,168 DS1s (T-1s) and equivalent to 256 DS3s (T-3s). See also Concatenation, OC-1, OC-N and SONET.


Optical Carrier-level 768. A SONET and DWDM transmission rate of 39.812 Gbps, OC-768 currently is the highest speed level defined for SONET. OC-768 is the equivalent of sending seven CDs full of data every second. See also Concatenation, OC-1, OC-N and SONET.


Optical Carrier-number. The optical interface designed to work with the STS-n signaling rate in a Synchronous Optical Network (SONET). The optical signal that results from an optical conversion of an STS-N signal. N= 1, 3, 9, 12, 18, 24, 36, 48, 192, 256, or 768. See also Concatenation, OC-1, OC-N and SONET.


Other Common Carrier. A long distance carrier other than AT&T. When AT&T was the major long distance carrier in North America, other long distance carriers were called (guess what?) "other common carrier." Now there are many, and AT&T's share of the long distance market is much smaller, the term is no longer used much (except at AT&T). These long distance companies (including AT&T) are now called IntereXchange Carriers (IXCs, or IECs).

Occam's Razor

"Pluralitas non est ponenda sine neccesitate" or "plurality should not be posited without necessity." In other words, one should not increase, beyond what is necessary, the number of entities required to explain anything. Also known as the "principle of unnecessary plurality," the "principle of parsimony" and "the principle of simplicity," Occam's Razor is a principle of logic attributed to William of Ockham (ca. 1285- 1349), a medieval English philosopher and Franciscan monk. Occam's Razor essentially means that the simplest plausible explanation that fits the facts is the best. The application of Occam's Razor might lead you to first investigate the electrical circuit powering a computer system such as a PC, PBX or central office. Many system failures and performance problems are the result of dirty power, improper grounding or the buildup of corrosion or dirt on connectors. In physics, razor refers to the method by which one cuts away at metaphysical concepts, eliminating those elements of an explanation that cannot be observed by the scientific method.


  1. The time a circuit or a switch is in use, i.e. occupied. Occupancy is normally expressed as a percentage, occupancy represents the actual usage versus the maximum amount of time available during a 1- hour period.

  2. A call center term. The percentage of the scheduled work time that employees are actually handling calls or after-call wrap-up work, as opposed to waiting for calls.


Optical Code Division Multiple Access is a variation on the CDMA theme used in RF (Radio Frequency) based networks. OCDMA begins with an inexpensive incoherent light source, i.e., an LED (Light Emitting Diode) light source generating light signals comprising multiple wavelengths which are not necessarily in phase. Programmable optical filters then are used to filter out specific wavelengths of light in the signal, creating an optical signal with a unique spectral signature, that conceptually resembles a barcode . Multiple OCDMA signals can be introduced into and can coexist on the same fiber, with each comprising a unique channel. OCDMA is proposed by some as a much less expensive alternative to DWDM (Dense Wavelength Division Multiplexing). DWDM requires multiple finely tuned lasers, one for each channel, at each point that channels are added to or dropped from the fiber. OCDMA replaces these with inexpensive passive optical filters, with OCDMA gear residing only at the entry and exit points of the network. See also CDMA, Coherent Light, DWDM, and Incoherent.


See Open Collaboration Environment.


See Optical Channel.


Office Code Location.


Operating Company Number. A code used in the telephone industry to identify a telephone company. Company codes assigned by NECA (National Exchange Carriers Association) may be used as OCNs. See also AOCN and NECA.


See Optical Character Recognition or Outgoing Call Restriction.

OCR Automatic Routing

Implemented by Optus and others, this technique also assigns a number to each user up to four digits long. The sender types this number within double parentheses anywhere on the cover sheet of a fax transmission, and the LAN-net- worked fax system uses optical scanning technology to read the number and route the fax to the intended recipient's workstation.


The Ottawa Centre for Research and Innovation, brings together industry, govt. and universities. See www.ocri.ca.


A numbering system with the base eight.


Also spelled Octothorpe, Octotherp, or Octothorp. The character on the bottom right of your touchtone keyboard, which is also typically above the 3 on your computer keyboard. It's commonly called the pound sign, but it's also called the number sign, the crosshatch sign, the tic-tack-toe sign, the enter key, the octathorp (also spelled octothorpe) and the hash. On some phones it represents "NO." And on others it represents "YES." Most U.S. long distance companies use it as the key for making another long distance credit card call without having to punch in your authorization code again. Here is the origin of this term in telephony. One day many moons ago, AT&T wanted to make sure that every symbol on the telephone keypad had a proper name that can be used in their manuals and user's guides that is published for every product that they made. Initially, the phone keypad had two strange looking symbols one under the 7 and looked like a "star", and the other under the 9 and looked like a "diamond". These two characters were actually impressed on these two keys. The problem with these two symbols was that they were not available on any typewriter or a printing operation of the time, hence AT&T decided to change them to something that was available on a standard typewriter. So they checked all the available symbols on a typewriter and found that the closet match to the "star" was the "*" which is properly referred to as the "asterisk", and the closest match to the "diamond" was the "#", or the "number sign". The problem with the "#" symbol was that it didn't officially have a proper name. It had many descriptions as the number sign, or the pound sign, or the crosshatch sign, the tic-tac-toe sign, or the hash key, but not a proper name like the asterisk. In the English language, most printed characters have a name, for example, the dot "." carries the name of "period", the "&" sign carries the name of "ampersand", and the "!" carries the name of "exclamation mark". So, on a rainy afternoon in the summer of 1965, several employees of AT&T marketing department on Church Street in New York City after a heavy luncheon meeting, were contemplating this particular problem of a name for the "number sign". After studying the character for a while, one of the men present noted that there were eight spaces around the outside of the character and he proposed that the name of this character should begin with the Greek word "Octo" which means eight. Another fellow, in jest, suggested this should be followed by a sound which is unique in the English language and he proposed the letters "th". In reality, the sound of the letters "th" is very unique to the English language, and no other language has anything like it ( I checked in over 50 languages, and found none has a sound like "th", some were close but never the same). A psychologist in the group suggested that the word should end very positively with a hard ending to have a good impact on the name. While they were contemplating what should the ending be, another chap who apparently was having some stomach problems since lunch , gave vent to a mild long belch "burrrrpppp" which one of the conspirators seized upon to make the ending of the word "erp"!! The name of the number sign immediately became "Octotherp". Later in time, as the word gaind in usage, people who were unaware of its genesis began to question the lexical background of the word. Although there was little discussion about "Octo", the rest of the word "therp" could not be found in any dictionary or encyclopedia. The nearest anyone could think of was the old Saxon word "thorp" meaning a village or hamlet, like the birthplace of Sir Isaac Newton was Woolsthorp. As a result, the spelling of the word was changed to "Octothorp" by an English language professor at McGill University in Montreal who was asked by Bell Canada to find the origin of the word "Octotherp", since they were planning to use it in their printed manual and user's guides. The professor was unable to account for the origin of the word and thought it was a misprint or a typo and "corrected" the word to "Octothorp". Thanks to Elias Zaydan for the explanation. His email address: elias@canada.com.


An eight-bit byte.

Octets received OK

The number of octets (bytes) received without error.


A 25-pair cable that at one end has an amphenol connector (typical of what 1A2 phone systems were connected with) and at the other has many individual 2, 4, 6 and 8 wire connectors, typically male RJ-11s. The reason it's called an octopus is that it looks a bit like an octopus ” one body and many arms. It's also called a Hydra.


The character on the bottom right of your touchtone keyboard, which is also typically above the 3 on your computer keyboard. It's commonly called the pound sign, but it's also called the number sign, the crosshatch sign, the tic-tack-toe sign, the enter key, the octothorpe (also spelled octathorp) and the hash. On some phones it represents "NO." And on others it represents "YES." Most US long distance companies use it as the key for making another long distance credit card call without having to redial. My friend Ralph Carlsen who worked at Bell Labs, wrote me, "First, where did the symbols * and # come from? In about 1961 when DTMF dials were still in development, two Bell Labs guys in data communications engineering (Link Rice and Jack Soderberg) toured the USA talking to people who were thinking about telephone access to computers. They asked about possible applications, and what symbols should be used on two keys that would be used exclusively for data applications. The primary result was that the symbols should be something available on all standard typewriter keyboards. The * and # were selected as a result of this study, and people did not expect to use those keys for voice services. The Bell System in those days did not look internationally to see if this was a good choice for foreign countries . Then in the early 1960s Bell Labs developed the 101 ESS which was the first stored program controlled switching system (it was a PBX). One of the first installations was at the Mayo Clinic. This PBX had lots of modern features (Call Forwarding, Speed Calling, Directed Call Pickup, etc.), some of which were activated by using the # sign. A Bell Labs supervisor Don MacPherson went to the Mayo Clinic just before cut over to train the doctors and staff on how to use the new features on this state of the art switching system. During one of his lectures he felt the need to come up with a word to describe the # symbol. Don also liked to add humor to his work. His thought process which took place while at the Mayo Clinic doing lectures was as follows :

  • There are eight points on the symbol so "OCTO" should be part of the name.

  • We need a few more letters or another syllable to make a noun, so what should that be? (Don MacPherson at this point in his life was active in a group that was trying to get JIM THORPE's Olympic medals returned from Sweden) The phrase THORPE would be unique, and people would not suspect he was making the word up if he called it an "OCTOTHORPE".

So Don Macpherson began using the term Octothorpe to describe the # symbol in his lectures. When he returned to Bell Labs in Holmdel NJ, he told us what he had done, and began using the term Octothorpe in memos and letters. The term was picked up by other Bell Labs people and used mostly for the fun of it. Some of the documents which used the term Octothorpe found their way to Bell Operating Companies and other public places. Over the years , Don and I have enjoyed seeing the term Octothorpe appear in documents from many different sources."


Office Channel Unit Data Port. A channel bank unit used to interface between the channel bank and a customer's DDS CSU or DSU.


Ole Custom Control. According to InfoWorld, OCXes are the core of Microsoft's plans for packaging prewritten code that can be downloaded from Web servers.


Office Document Architecture. ISO's standard 8613-1/8 for document architecture and interchange format adopted by MAP/TOP 3.O, GOSIP, and standardized by ECMA as ECMA-101.


ODBC ” Open DataBase Connectivity ” is a way of writing software in one program so you can get access to data in another program. A simple idea: You company might be a have sales order entry system. You may wish to tie that system to a inventory system. You join the two program with ODBC. More formally , ODBC is a standard database access method developed by Microsoft (September 1992), based on the Call-Level Interface (CLI) defined by the SQL (Structured Query Language) Access Group, which now is part of The Open Group. ODBC is a standardized API (Application Programming Interface) that provides a set of functions for access to databases. Independent of database format, ODBC supports access to both relational and non-relational databases. Thereby, a wide range of database programs (e.g. Microsoft Access, Microsoft Excel, Oracle and Xbase) can be accessed by a common interface. ODBC allows one to write an application that links to an appropriate ODBC driver, which translates ODBC requests into the native format for a specific file source (i.e., database).

ODBC Compliant

Your software is ODBC compliant if it can talk to and access other ODBC databases. See ODBC.

Odd Ball Day

A telephone company term. A day experiencing an extremely heavy traffic load caused by an event that is not expected to reoccur. The data would be excluded from the engineering historical base.

Odd Parity

One of many methods for detecting errors in transmitted data. An extra bit is added to each character sent and that bit is given a value of 0 ("zero") or 1 ("one") such that the total number of ones in the character (including the parity bit) will be odd.


Optical Distribution Frame.


Open Data-link Interface. A device driver standard from Novell. ODI allows you to run multiple protocols on the same network adapter card. Interconnectivity strategy that adds functionality to Novell's NetWare and network computing environments by supporting multiple protocols and drivers. ODI's benefits allow you to:

  • Expand your network by using multiple protocols without adding network boards to the workstation. ODI creates a "logical network board" to send different packet types over one board and wire.

  • Communicate with a variety of workstations, file servers, and mainframe computers via different protocols without rebooting your workstation.

  • Configure the LAP driver for any possible hardware configuration with NET.CFG, instead of using limited SHELL.CFG choices.


Original design manufacturer. From Business Week of June 17, 2002: "Few products have won Compaq Computer as much favorable buzz as the sleek ipaq Pocket PC. But Compaq, now part of Hewlett-Packard, neither designed nor made the ipaq. The handheld and its clever system of interchangeable accessory sleeves were products of a Taiwanese company called HTC (www.htc.com.tw), one of an increasingly important breed known in the trade as original design manufacturers, or ODMs. PC makers have been using contract manufacturers to build many of their products for years. Even IBM, one of the last U.S. companies to do most of its own manufacturing, has contracted out all of its desktops and some ThinkPads. What's new here is the farming out of the design work as well. The amount of involvement by the "name" company ranges from extensive modifications of the ODM's work to simply slapping a logo on an off-the-shelf product. Some ODMs, such as South Korea's Samsung and LG Electronics or Taiwan's Acer, market product lines under their own brands, too. Others, such as HTC and Quanta, also Taiwanese, exist almost entirely on contract work. If consumers can't tell who makes laptops or even who designs them, how are they to choose? In the final tally, what really matter are the intangibles, such as the warranty, the service, and the tech support provided by the dealer and the company whose brand is on the product."


Open Distributed Processing.


Open Directory Services Interface. Announced by Microsoft in the summer of 1995, two years after Novell's NetWare Directory Services (NDS), it is designed to do essentially what NDS does, namely give users a way to sign on to multiple servers through one simple sign-on. The ultimate idea is that NDS or ODSI will become a single place for a networked user (i.e. one on a local area network ” a LAN) to sign on to multiple networked devices, e.g. telephone systems, voice mail, electronic mail, Lotus Notes and, of course, multiple file servers (wherever they're located). Sign on in one place, get into many. A big user time-saving benefit.


Original Equipment Manufacturer. This term is confusing. An OEM maker is a manufacturer of original equipment. Intel is an OEM, because it makes semiconductors, though it in turn buys raw silicon from somebody else. Compaq, Dell or Gateway are not OEMs, since they buy their components from someone else and simply assemble the components into PCs and servers. They manufacture very little. They are often called value-added resellers .


Optical-Electrical-Optical. Conventional fiber optic transmission systems generally are not purely optical in nature. Rather, the signal always begins and ends life as electrical, as the connected computer systems (e.g., concentrators , multiplexers, switches, and routers) are electrically-based. So, the signal is converted from electrical to optical format in order to be sent over the transmission system, and ultimately must be converted back into electrical format at the receiving computer system. Now, over a distance, the optical signal attenuates (i.e., weakens) to the point that it must be boosted. Usually, that boosting unit is in the form of a regenerative repeater, which is an OEO device. That is to say that the incoming optical (O) signal is converted to electrical (E) format, boosted in signal strength and filtered for noise, and the outgoing signal is converted back into (O) optical format as it exits the repeater. It works just fine, but OEO repeaters are expensive, are prone to failure, require local power, and must be upgraded as network speeds increase. OOO (Optical- Optical-Optical) techniques have been developed in the forms of Erbium-Doped fiber Amplifiers (EDFAs) and Raman amplifiers , which generally are considered to be substantial improvements over OEO repeaters. See also EDFA, Raman Amplifier , and Repeater.


Orthogonal Frequency Division Multiplexing. A modulation technique for wireless communications, OFDM was patented by Bell Labs in 1970, and initially was used in a naval communications system dubbed Catherine. Much like DMT (Discrete MultiTone), OFDM splits the datastream into multiple RF (Radio Frequency) channels, each of which is sent over a subcarrier frequency. DMT and other more conventional techniques encode data symbols for a given data stream onto one radio frequency. In an OFDM system, however, each tone (i.e., frequency) is orthogonal (i.e., independent or unrelated) to the other tones; multiple data symbols are encoded concurrently onto multiple tones in a parallel fashion. The signal-to-noise ratio of each of those very precisely defined frequencies is carefully monitored to ensure maximum performance. OFDM eliminates the requirement for guard bands to separate the frequencies and, thereby, avoid interference from adjacent RF channels. Guard bands are required only around the edges of a set of tones, i.e., RF channels. This yields greater spectral efficiency, as virtually all of the allocated RF spectrum can be used for data transmission. OFDM is based on the mathematical concept of FFT (Fast Fourier Transform), which allows individual channels to maintain their orthogonality (i.e., distance) to the adjacent channels. As OFDM makes use of many narrowband tones, frequency selective fading due to multipath propagation degrades only a small portion of the signal, and has little or no effect on the remaining RF components. As a result, OFDM can eliminate line-of-sight requirement for fixed wireless systems, also known as WLL (Wireless Local Loop). "Orthogonal," by the way, is from the Greek "orthos" and "gonia," translating into "straight angle," i.e., perpendicular .

OFDM is used by the HomePlug Powerline alliance to avoid line noise in a residential power-line network. How It Works:

  1. Broadband content from cable modem, DSL or satellite is fed to home gateway.

  2. By plugging gateway into any electrical outlet, content is bridged to any HomePlug-enabled device.

  3. OFDM takes multiple signals of different frequencies and combines them to form one signal to avoid line "noise".

  4. HomePlug network monitors power lines for "noise." If noise occurs on a particular frequency, OFDM engine shifts transmission to another frequency.

See also DMT and WLL.


Jargon for "over the air." More correctly called "over the air" signals to avoid confusion between "on the air" and "off the air." See Over-the-Air.


When the handset is lifted from its cradle it's Off-Hook. When you lift the handset of many phones, the hookswitch is moved by a spring and alerts the central office that the user wants the phone to do something like receive an incoming call or dial an outgoing call. A dial tone is a sign saying "Give me an order." The term "off-hook" originated when the early handsets were actually suspended from a metal hook on the phone. When the handset is removed from its hook or its cradle (in modern phones), it completes the electrical loop, thus signaling the central office that it wishes dial tone. Some leased line circuits work by lifting the handset, signaling the central office at the other end which rings the phone at the other end; such circuits are known as "ring down circuits." Some phones have autodialers in them. Lifting the phone signals the phone to dial that one number. An example is a phone without a dial at an airport, which automatically dials the local taxi company. All this by simply lifting the handset at one end-going "off-hook." See also Ring Down Circuit.

Off-Hook Call Announce

A telephone system feature. A telephone has a speaker. If the person is speaking on the phone, another person (inside the building, on the same phone system) can "off-hook voice announce" you and can give you a message or speak with you. You will hear their voice coming through the speaker on your phone. (So may the person on the other end.) Depending on your phone, you may be able to put your hand over your telephone handset and whisper something back to the person who's "off-hook voice announcing" you. Otherwise you'll have to hang up or put the person on hold, and speak to the person on another line.

Off-Hook Queue

There are two types of queuing: ON-HOOK and OFF-HOOK. In On- Hook Queuing, the user dials his number, the switch tells him the outgoing trunks are busy.

The user then hangs up. The switch calls him back when a trunk becomes available. In Off- Hook dialing, the user waits with his receiver screwed into his ear until a trunk comes free and the PBX connects him to the next available trunk. Off-Hook queues are usually shorter than on-hook queues. If a trunk doesn't come free quickly in off-hook queuing, the call will often flow over onto the more expensive DDD trunks. Off-hook queuing costs more but keeps the user waiting less. On-hook queuing costs less by waiting for a cheaper trunk but can be tiring and frustrating for the workers waiting for their calls to go through.

Off-Hook Routing

See Off-Hook and Ringdown.

Off-Hook Voice Announce

See Off-Hook Call Announce.


Any equipment not actively connected to a phone line but which can be activated to work with that system is Off-Line. This concept also applies to computer systems. For example, a modem attached to or built into a microcomputer can be plugged permanently into a phone line. But the microcomputer can be used for word processing most of the time. While it's doing word processing, it is "off-line." When the user loads the communications software and turns on the modem, the microcomputer is now said to be "on line." Off-line computer storage is a place to put stuff which a computer cannot access "on- line," like a hard-disk . Off-line storage might be microfilm or microfiche.

Off-Line Storage

Storage that is not under the control of a processing unit.

Off-Net Calling

Phone calls which are carried in part on a network but are destined for a phone not on the network, i.e. some part of the conversation's journey will be over the public switched network or over someone else's network. MCI defines off-net calls as "Billable calls to non-tariffed cities. Can be MCI Off-Net or WATS Off-Net. Classified as Tier 2 for tariff purposes."

Off-Network Access Line

ONAL. A circuit in a private network which allows the user to go off the private network and complete calls on the public dial network.


The periods of time after the business day has ended during which carriers offer discounted airtime charges. Usually, OFF-PEAK rates are available for cellular calls between 7:00 p.m. and 7:00 a.m. and on weekends and holidays, but times vary among carriers. Among landline carriers, the business day usually ends at 5 p.m., after which time residential calling builds, and that ends at 11 p.m., after which little happens, except rates drop once again until they rise at the beginning of the next business day at 8 a.m. the next morning.

Off-Premises Extension

OPX. Now also called OPS for Off-Premises Station. A telephone located in a different office or building from the main phone system. The OPX is connected by a phone line dedicated to it. It acts as if it were in the same place as the main phone system and can use its full capabilities. Here's another explanation a reader sent in. OPX is the appearance of an actual telephone line (such as 212-691-8215) in two physically separate locations. For example, this line (212-691-8215) could appear and ring in my office and at my home without my home phone being a part of the office telephone system. An OPX is commonly used for answering services or for small businesses. Bell operating phone companies are sharply increasing the charge for dedicated OPS lines ” often by several hundred percent per year.

Off-Site Night Answer

A feature of some phone systems that allows phone calls to the main line to be forwarded to another phone line after hours.


Euphemism for being off the Net. "Sorry I didn't email you last week; I was off the grid in Europe." Off-the-grid also refers to someone who lives in a rural area without running water, electricity or phone service.


When something has already been produced and is available for immediate delivery, it is said to be available "off-the-shelf." It is presumably sitting on the shelf in a warehouse waiting for your order. Sometimes called "shrinkwrapped," referring to the plastic wrap around the box. It means you don'1t are not meant to need intervention by a programmer or integrator to make the software work.

Off/On Hook

A modem term. Modem operations which are the equivalent of manually lifting a phone receiver (taking it off hook) and replacing it (going on hook). See ff-Hook.

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

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