Computer Telephony Terms and Technologies

Definitions for computer telephony terms and technologies.

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Asynchronous transfer mode (ATM): Acommunications standard that includes hardware and signaling (such as Ethernetand Token Ring) at speeds ranging from 25Mbps to more than 655Mbps. Among ATM'sfeatures is the ability to dedicate bandwidth to particular conversations.Although touted as a replacement for Ethernet, ATM is much more important in theinterconnect market. ATM drivers are available for Windows NT but currently useLAN emulation, so they can't directly reserve channels for individualconversations.

Automatic Call Distribution (ACD): Asystem that answers incoming calls to a call center and transfers them to liveemployees generally in the order in which the calls came in. Often, the ACDsystem can interpret caller ID or ANI information and route calls to theappropriate employees after retrieving the callers' records from the corporatedatabase.

Automatic number identification (ANI): Informationthat comes in at the beginning of each call, usually with in-band MultifrequencyDigits (MF) or digitally on an Integrated Services Digital Network (ISDN) Dchannel. ANI provides terminating CT equipment with the calling party's phonenumber, so that you immediately know the caller's identity. Companies often useANI with 800, 888, and 900 phone numbers.

Automatic speech recognition (ASR): Afeature that lets computers interpret and respond to spoken commands. A popularPC-based ASR application is the talking typewriter (e.g., IBM and Kurzweil). CTapplications let you control voicemail, auto attendant, and interactive voiceresponse (IVR) systems using the spoken word instead of a touch-tone phone.Generally, when a large number of people use the ASR system, it supports alimited vocabulary of a few dozen words. When only one person uses the ASRsystem (i.e., speaker-dependent ASR), you can train it to recognize a muchlarger vocabulary.

Channel: A dedicated or apparentlydedicated unit of bandwidth. The bandwidth of analog phone calls, for example,is 56Kbps or 64Kbps. The communications industry often aggregates analog callsinto T-1s. LANs, WANs, and the Internet are packet-based, and therefore, have noway to dedicate bandwidth to a particular conversation.

Component Object Model/Distributed ComponentObject Model (COM/
DCOM): A protocol for program and data objects tocommunicate either inside a computer (COM) or over a network (DCOM). DCOMoriginated from Network Object Linking and Embedding (OLE) and isMicrosoft-centric, although it's based on the Open Group's (formerly the OpenSoftware Foundation) Distributed Computing Environment­Remote ProcedureCall specification. Some CT applications use DCOM for interprocesscommunications. DCOM's competitors include Common Object Request BrokerArchitecture (CORBA) and the almost dead OpenDoc.

Computer telephony (CT): A technology thatapplies computer intelligence to the making, receiving, and managing of phonecalls. In other words, CT systems automatically handle and process phone calls.CT systems often let you use a touch-tone phone or spoken commands to controlvarious aspects of calls. CT products include voice and fax messaging, autoattendants, fax-on-demand (FOD), fax servers, and IVR. Core technologies includevoice recognition (ASR), text-to-speech conversion, and the Internet.

Computer telephone integration (CTI): Aclass of CT systems that interconnect a local PBX or ACD system to a computersystem. With CTI, you can control calls by clicking controls on a computerinstead of pushing buttons on a touch-tone phone.

Dialed Number Identification Service (DNIS):A feature that sends the dialed phone number to the terminating CT equipment.DNIS lets CT systems use the same equipment to handle different called numberswith different greetings and applications. Companies often use DNIS with 800,888, and 900 phone numbers.

Direct Inward Dialing (DID): A specialtrunk phone line that passes the last two to four digits of the dialed phonenumber to the terminating CT equipment. DID requires special hardware to readthese digits.

Fax-on-demand (FOD): A system that letsyou use a touch-tone phone to receive stored documents on your fax machine.Documents can be data sheets, spreadsheets, scanned pages, or any otherprintable material. Some FOD systems support faxing Web-based documents, whichtheoretically lets you maintain only one set of documents instead of two (onefor the Web and the other for the FOD system).

Fax over IP (FoIP): An emerging method ofsending faxes over the Internet, either to an IP fax server or another phoneline. FoIP is different from traditional organizationwide fax solutions in thatit sends the much smaller source material (e.g., cover sheet and Word document)over the Internet to the fax server nearest the dialed number.

Fax server: A LAN-based server thatmanages all incoming and outgoing fax traffic for an organization. A fax serverprovides centralized management of corporate fax functions. It also enablesdesktop faxing without your installing
a fax card or fax phone line ateach desktop computer. Companies often integrate a fax server with MicrosoftExchange or Outlook so that employees visually manage incoming faxes in theirinboxes.

First-party call control: The ability tocontrol calls that come to your phone. Microsoft's Telephony API (TAPI) definesa set of commands that let you answer, transfer, park, and forward calls.

H.100: A standard for a physical CT businterface layer for the PCI computer chassis card slot. H.100 will drive newapplications and open new markets.

H.323: A group of International TelegraphUnion standards for packet-based videoconferencing. (Previously, the standardfor circuit-switched video teleconferencing was H.320.) H.323 is applicable toInternet video because it's based on the Internet Engineering Task Force'sRealtime Protocol/Realtime Transport Control Protocol. LAN and WANteleconferencing often uses H.323, but people often experience significant setupand interoperability problems with it. These problems hamper H.323's widespreaduse.

Inbound calls: An incoming call thatterminating CT equipment answers. For example, if you call a company's voicemailsystem, your call is inbound to that system.

Interactive voice response (IVR): A systemthat lets you request information, usually stored in databases, by pressing keyson a touch-tone phone. Automated bank-by-phone services and automated flightinformation are two examples of IVR.

IP telephony: A generic term for movingvoice and fax over TCP/IP networks.

Java Telephony API (JTAPI): A robust,vendor-independent method of communicating between computers and switches,especially in Web browser-based telephony applications. You can layer JTAPI onTAPI or use JTAPI natively with switches supporting it. JTAPI is SunMicrosystems' extension to telephony control.

Messaging API (MAPI): The Microsoftstandard for communicating messages (especially email) between applications,either intramachine or on a LAN. People often consider MAPI as a prototype COMAPI.

Multi-Vendor Integration Protocol (MVIP):A time-division bus and signaling standard for connecting call-processing boardswithin one chassis or box. In other words, MVIP provides a way for multipleboards to communicate and to pass and signal calls. MVIP has multiple standardsof differing densities and usage. MVIP also refers to the GO-MVIP standardsbody.

Open Database Connectivity (ODBC): Thelink between a CT application and a database back end. Many vendors write CTapplications in Visual Basic (VB). When you use VB, SQL front ends are expensiveand difficult to develop. Therefore, vendors use ODBC, which is standard withVB, to link to SQL.

Outbound calls: A call that CT equipmentplaces. For example, if a company's voicemail system sends a message to yourpager, the system places an outbound call.

Plain old telephone service (POTS) lines:Analog, twisted-pair phone lines that connect analog telephones andtelecommunications devices. Each POTS line uses two active wires. You need touse a modem to send digital data, faxes, and so forth on analog lines.

Public Switched Telephone Network (PSTN): Anetwork that lets you make and receive telephone calls (i.e., not Internetcalls).

ReSerVation Protocol (RSVP): An evolvingstandard to make routers prioritize time-urgent communications. Windows NT 5.0will have built-in RSVP.

S.100: A standard that defines a set ofOS-independent APIs for developing CT applications in an open environment.Applications are portable between S.100-compliant platforms because S.100'sclient/server model abstracts implementation details of CT hardware and switchfabrics. S.100 is not object oriented (OO). A future S.x00 standard will be OO.

Signal Computing System Architecture (SCSA):An architectural standard for CT hardware and software components. SCSA definesphysical interconnecting switching fabric for CT peripherals and more. Manyvendors of CT hardware and applications support SCSA. Dialogic launched SCSA in1993.

Signaling System 7 (SS7): An out-of-bandsignaling scheme. With SS7, terminating CT equipment makes faster callconnections, provides information on who's calling (like ANI does), and providesenhanced call features (such as call forwarding)--all without a PBX. The entirephone network becomes a huge computer-controlled switch with SS7.

SQL (Structured Query Language): Thestandard for organization-level database queries. Notable Windows NT SQLdatabase providers include Oracle, Sybase, and Microsoft.

Switch: Slang for PBX or phone system. Theswitch is the box that all phones within an organization connect to.

T-1: A unit of digital bandwidth totaling1.544Mbps, or 24 simultaneous full-voice channels. T-1, which the US uses formost of its communications, is often cut into fractional units. In Europe, E-1(2.048Mbps) fills the same role as T-1, but supports 30 channels. On robbed-bitimplementations, both E-1 and T-1 take bits from the overall bandwidth fortiming and signaling, slightly lowering the available bandwidth of each channel.

Telephone user interface (TUI): Aninterface that lets you use a touch-tone phone to control a CT application. Yousimply listen to recorded prompts and respond using the phone's buttons.

Telephony API (TAPI): The standard thatWindows 95 and Windows NT use to communicate with phone systems. TAPI 1.0appeared with Win95 and NT 3.51; TAPI 2.0 came with NT 4.0. TAPI 2.1 is inpublic beta and adds client/server functions, which are necessary fororganizationwide solutions. TAPI 3.0 will be out with NT 5.0.

Telephony Services API (TSAPI): Thestandard that Novell NetWare systems use to communicate with phone systems.

Text-to-speech (TTS) conversion: Atechnology that lets CT systems verbally relay text information withoutpreviously recording it. TTS works very effectively with IVR systems. Forexample, with TTS, an IVR system can retrieve an address from a large databaseof addresses and verbally tell the caller that address. This technology ispreferable to recording each address as a separate speech prompt when the numberof prompts is very large. With TTS, you can use a phone to retrieve emailmessages from a unified messaging system. This technology is especially usefulfor applications in which rapidly changing database information needs to bespoken.

Third-party call control: The ability tocontrol a phone call that is not directly connected to your computer.Third-party call control usually requires TAPI 2.0 or later and a directconnection from the computer to the telephone switch (e.g., via Ethernet).

Unified messaging: A simple concept thatcan save you time and effort. In a unified messaging system, all yourmessages--voice, email, fax, and data (such as documents)--go into a unifiedinbox. Everything in the inbox is accessible from a desktop PC, phone, or laptopcomputer.

UnPBX: A CT server that usescall-processing boards to provide all functions of a PBX, voicemail, autoattendant, and ACD system. UnPBX systems can use traditional and PC-basedphones.

Voice over IP (VoIP): An emerging methodfor sending voice over the Internet, an intranet, or an extranet. Although VoIPsuffers from such problems as dropped packets, variable delivery times,unpredictable bandwidth, and variable speech quality, many long-distance callersuse VoIP because it saves them money.

Voice Profile for Internet Mail (VPIM): Anumbrella standard for attaching voice (and related material) to email messages,especially over the Internet. VPIM supports many intersystem voice and faxmessaging functions, including nondelivery notification, message privacy, andpriority mail. De facto limits on email attachment size hamper thisstandard's use as a universal inbox and follow-me service for all email,voicemail, and faxes.

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