Glossary

 A-law: Pulse Code Modulation (PCM) algorithm used in digitizing telephone audio signals in E-1 areas. See also Mu-law.

 Adaptive Differential Pulse Code Modulation: See ADPCM.

 ADPCM (Adaptive Differential Pulse Code Modulation): A compression algorithm for digitizing audio that stores the differences between successive samples rather than the absolute value of each sample. This method of digitization reduces storage requirements from 64K bits/second to as low as 24K bits/second.

 ADSI (Analog Display Services Interface): A Bellcore standard defining a protocol for the flow of information between a switch, a server, a voice mail system, a service bureau, or a similar device and a subscriber's telephone, PC, data terminal, or other communicating device with a screen. The idea of ADSI is to add words to a system that usually only uses touch tones. In a typical voice mail system, you call up and hear choices: "to listen to new messages, press 1, to hear saved messages, press 2," etc. ADSI is designed to display the choices you're hearing on a screen attached to your phone. ADSI's signaling is DTMF and standard Bell 202 modem signals from the service to your 202-modem-equipped phone. From the phone to the service it's only touch tone. ADSI works on every phone line in the world.

 AGC (Automatic Gain Control): An electronic circuit used to maintain the audio signal volume at a constant level.

 AMIS (Audio Messaging Interchange Specification): A series of standards aimed at addressing the problem of how voice messaging systems produced by different vendors can network or inter-network. It deals specifically with the interaction of the systems and does not affect the systems themselves. There are two specifications: 1. AMIS-digital: All the control information and the voice messages are ported between systems digitally. 2. AMIS-analog: Control information and messages are transferred in analog form. For AMIS specifications, call Hartfield Associates (Boulder, CO) at (303) 442-5395.

 analog: 1. A method of telephony transmission in which the signals from the source (for example, speech in a human conversation) are converted into an electrical signal that varies continuously over a range of amplitude values analogous to the original signals (as opposed to digital signaling). 2. Used to refer to applications that use loop start signaling.

 ANI: Automatic Number Identification.

 API: See Application Programming Interface.

 Application Programming Interface: A set of standard software interrupts, calls, and data formats that application programs use to initiate contact with network services, mainframe communications programs, or other program-to-program communications.

 ASCIIZ string: A null-terminated string of ASCII characters.

 asynchronous function: A function that allows program execution to continue without waiting for a task to complete. To implement an asynchronous function, an application-defined event handler must be enabled to trap and process the completed event. See synchronous function.

 AT: An IBM or IBM-compatible Personal Computer (PC) containing an 80286 or higher microprocessor, a 16-bit bus architecture, and a compatible BIOS.

 AT bus: The common communication channel in a PC AT. The channel uses a 16-bit data path architecture, which allows up to 16 bits of data transfer. This bus architecture includes the standard PC bus plus a set of 36 lines for additional data transmission, addressing, and interrupt request handling.

 Automatic Gain Control: See AGC.

 base memory address: A starting memory location (address) from which other addresses are referenced.

 bit mask: A pattern which selects or ignores specific bits in a bit mapped control or status field.

 bitmap: An entity of data (byte or word) in which individual bits contain independent control or status information.

 board device: A board-level object that can be manipulated by a physical library. Board devices can be real physical boards, such as a D/4x board, or virtual devices, such as one of the D/4x boards that is emulated by a D/xxxSC board.

 Board Locator Technology (BLT): Operates in conjunction with a rotary switch to determine and set nonconflicting slot and IRQ interrupt-level parameters, thus eliminating the need to set confusing jumpers or DIP switches.

 buffer: A block of memory or temporary storage device that holds data until it can be processed. It is used to compensate for the difference in the rate of the flow of information (or time occurrence of events) when transmitting data from one device to another.

 bus: An electronic path which allows communication between multiple points or devices in a system.

 busy device: A device that is stopped, being configured, has a multitasking or nonmultitasking function, or I/O function active on it.

 cadence: A rhythmic sequence or pattern. Once established, it can be classified as a single ring, a double ring, or a busy signal by comparing the periods of sound and silence to establish parameters.

 cadence detection: A voice driver feature that analyzes the audio signal on the line to detect a repeating pattern of sound and silence.

 Call Progress Analysis: The process used to automatically determine what happened after an outgoing call is dialed. Also referred to as call analysis or call progress.

 Call Status Transition Event Functions: Functions that set and monitor events on devices.

 CCITT (Comite Consultatif Internationale de Telegraphique et Telephonique): One of the four permanent parts of the International Telecommunications Union, a United Nations agency based in Geneva. The CCITT is divided into three sections: 1. Study Groups set up standards for telecommunications equipment, systems, networks, and services. 2. Plan Committees develop general plans for the evolution of networks and services. 3. Specialized Autonomous Groups produce handbooks, strategies, and case studies to support developing countries.

 Central Office: See CO.

 channel device: A channel-level object that can be manipulated by a physical library, such as an individual telephone line connection. A channel is also a subdevice of a board. See subdevice.

 channel: 1. When used in reference to a Dialogic analog expansion board, an audio path, or the activity happening on that audio path (for example, when you say the channel goes off-hook). 2. When used in reference to a Dialogic digital expansion board, a data path, or the activity happening on that data path. 3. When used in reference to a bus, an electrical circuit carrying control information and data.

 CO (Central Office): A local phone network exchange, the telephone company facility where subscriber lines are linked, through switches, to other subscriber lines (including local and long distance lines). The term "Central Office" is used in North America. The rest of the world calls it PTT, for Post, Telephone and Telegraph.

 computer telephony (CT): The extension of computer-based intelligence and processing over the telephone network to a telephone. Sometimes called computer-telephony integration (CTI), it lets you interact with computer databases or applications from a telephone, and enables computer-based applications to access the telephone network. Computer telephony technology supports applications such as: automatic call processing; automatic speech recognition; text-to-speech conversion for information-on-demand; call switching and conferencing; unified messaging that lets you access or transmit voice, fax, and e-mail messages from a single point; voice mail and voice messaging; fax systems including fax broadcasting, fax mailboxes, fax-on-demand, and fax gateways; transaction processing such as Audiotex and Pay-Per-Call information systems; and call centers handling a large number of agents or telephone operators for processing requests for products, services, or information.

 configuration file: An unformatted ASCII file that stores device initialization information for an application.

 Configuration Functions: Functions that alter the configuration of devices.

 Convenience Functions: Functions that simplify application writing.

 data structure: Programming term for a data element consisting of fields, where each field may have a different type definition and length. A group of data structure elements usually share a common purpose or functionality.

 debouncing: Eliminating false signal detection by filtering out rapid signal changes. Any detected signal change must last for the minimum duration as specified by the debounce parameters before the signal is considered valid. Also known as deglitching.

 deglitching: See debouncing.

 device: A computer peripheral or component controlled through a software device driver. A Dialogic voice and/or network interface expansion board is a board containing one or more logical board devices. Each channel or time slot on the board is considered a device.

 device channel: A Dialogic voice data path that processes one incoming or outgoing call at a time (equivalent to the terminal equipment terminating a phone line). There are 4 device channels on a D/4x, 8 on a D/80SC, 16 on a D/160SC, 24 on a D/240SC, 30 on a D/300SC, 32 on a D/320SC, 48 on a D/480SC-2T1, and 60 on a D/600SC-2E1 board. See also time slot.

 device driver: Software that acts as an interface between an application and hardware devices.

 device handle: Numerical reference to a device, obtained when a device is opened using xx_open( ), where xx is the prefix defining the device to be opened. The device handle is used for all operations on that device.

 Device Management Functions: Functions that open and close devices.

 Device name: Literal reference to a device, used to gain access to the device via an xx_open( ) function, where xx is the prefix defining the device to be opened.

 DIALOG/HD (Dialogic High Density) boards: Dialogic voice and telephone network interface resource boards having 8 or more ports. All DIALOG/HD boards use Board Locator Technology and can communicate via the SCbus.

 Digital signal processor: see DSP.

 digitize: The process of converting an analog waveform into a digital data set.

 download: The process where board level program instructions and routines are loaded during board initialization to a reserved section of shared RAM.

 downloadable SpringWare firmware: Software features loaded to Dialogic voice hardware. Features include voice recording and playback, enhanced voice coding, tone detection, tone generation, dialing, call progress analysis, voice detection, answering machine detection, speed control, volume control, ADSI support, automatic gain control, and silence detection.

 driver: A software module which provides a defined interface between an application program and the firmware interface.

 DSP: 1. Digital signal processor. A specialized microprocessor designed to perform speedy and complex operations upon digital signals. 2. Digital signal processing.

 DTMF (Dual-Tone Multi-Frequency): Push-button or touch-tone dialing based on transmitting a high- and a low-frequency tone to identify each digit on a telephone keypad. The tone frequencies are, in Hz:

1: 697, 1209	2: 697, 1336	3: 697, 1477
4: 770, 1209	5: 770, 1336	6: 770, 1477
7: 852, 1209	8: 852, 1336	9: 852, 1477
0: 941, 1336	*: 941, 1209	#: 941, 1477

 DualSpan board: A Dialogic voice board that has connections for two E-1 or T-1 lines.

 E-1: A CEPT digital telephony format devised by the CCITT. A digital transmission channel that carries data at the rate of 2.048 Mbps (DS-1 level).

 echo: The component of an analog device's receive signal reflected into the analog device's transmit signal.

 echo cancellation: Removal of echo from an echo-carrying signal.

 echo-cancelled signal: The output signal of an echo canceller after echo has been removed from the echo-carrying signal.

 echo canceller: The software component responsible for performing echo cancellation.

 echo-carrying signal: In regard to the echo canceller, a signal containing incoming speech data plus an echo component.

 echo-producing circuit: Typically the interface between 4-wire (typically digital) and 2-wire (typically analog) circuits, which, due to impedance mismatches, reflects part of the receive signal into the transmit signal.

 echo reference signal: The signal that initially introduced echo into the echo-carrying signal. This signal is used by the echo canceller to estimate the echo component in the echo carrying signal.

 ECR: Dialogic Echo Cancellation Resource, consisting of three Voice library function APIs for implementing echo cancellation on a Dialogic voice channel device.

 ECR mode: The operational mode for a Dialogic voice channel utilizing the Dialogic ECR feature at its highest level.

 ECR_RX: The receive signal of the voice channel device's echo canceller containing the echo reference signal.

 ECR_TX: The transmit signal produced by the voice channel device's echo canceller containing the echo-cancelled signal.

 event: An unsolicited or asynchronous message from a hardware device to an operating system, application, or driver. Events are generally attention-getting messages, allowing a process to know when a task is complete or when an external event occurs.

 event handler: A portion of a Dialogic application program designed to trap and control processing of device-specific events. The rules for creating a DTI/2xx event handler, for example, are the same as those for creating a Linux signal handler.

 Event Management functions: A class of device-independent functions (contained in the Standard Runtime Library) that connect events to application-specified event handlers, allowing users to retrieve and handle events that occur on the device. See Standard Runtime Library.

 Extended Attribute functions: A class of functions that take one input parameter (a valid Dialogic device handle) and return device-specific information. For instance, a voice device's Extended Attribute function returns information specific to the voice devices. Extended Attribute function names are case-sensitive and must be in capital letters. See Standard Runtime Library.

 firmware load file: The firmware file that is downloaded to a Dialogic voice board. This file has an .fwl extension.

 flash: A signal generated by a momentary on-hook condition. This signal is used by the voice hardware to alert a telephone switch that special instructions will follow. It usually initiates a call transfer. See also hook state.

 frequency detection: A voice driver feature that detects the tri-tone Special Information Tone (SIT) sequences and other single-frequency tones for call progress analysis.

 G.726: An ITU-T audio coding and decoding recommendation that defines the characteristics for conversion of a 64 Kbps A-law or _-law PCM channel at 8000 samples per second to and from a 40, 32, 24, or 16 Kbps channel. The conversion is applied to the PCM stream using an adaptive differential pulse code modulation (ADPCM) transcoding technique. G.726 is useful for applications that require speech compression, encoding for noise immunity, and uniformity in transmitting voice and data signals.

 Global Dial Pulse Detection (Global DPD): A Dialogic SpringWare firmware enhancement that enables computer telephony (CT) applications to respond to caller input originating from rotary or pulse dialing telephones.

 Global Tone Detection: A feature that allows the creation and detection of user-defined tone descriptions on a channel-by-channel basis.

 hook state: The current line status of the channel: either on-hook or off-hook. A telephone station is said to be on-hook when the conductor loop between the station and the switch is open and no current is flowing. When the loop is closed and current is flowing, the station is off-hook. These terms are derived from the position of the old fashioned telephone set receiver in relation to the mounting hook provided for it.

 hook switch: The circuitry that controls the on-hook and off-hook state of the voice device telephone interface.

 hybrid: See echo-producing circuit.

 I/O Functions: Functions that transfer data to and from devices.

 I/O: Input-Output.

 idle device: A device that has no functions active on it.

 In-band: The use of robbed-bit signaling (T-1 systems only) on the network. The signaling for a particular channel or time slot is carried within the voice samples for that time slot, thus within the 64 kbps (kilobits per second) voice bandwidth.

 in-band signaling: (1) In an analog telephony circuit, in-band refers to signaling that occupies the same transmission path and frequency band used to transmit voice tones. (2) In digital telephony, "in-band" means signaling transmitted within an 8-bit voice sample or time slot, as in T-1 "robbed-bit" signaling.

 Interrupt Request Level (IRL): Same as IRQ (See Interrupt Request).

 Interrupt Request (IRQ): A signal sent to the central processing unit to temporarily suspend normal processing and transfer control to an interrupt handling routine. Interrupts may be generated by conditions such as completion of an I/O process, detection of hardware failure, and power failures.

 kernel: A set of programs in an operating system that implement the system's basic functions.

 loop: The physical circuit between the telephone switch and the voice processing board.

 loop current: The current that flows through the circuit from the telephone switch when the voice device is off-hook.

 loop current detection: A voice driver feature that returns a connect after detecting a loop current drop.

 loop start: An electrical circuit consisting of two wires (or leads) called tip and ring, which are the two conductors of a telephone cable pair in an analog environment. The CO provides voltage (called "talk battery" or just "battery") to power the line. When the circuit is complete, this voltage produces a current called loop current. The circuit provides a method of starting (seizing) a telephone line or trunk by sending a supervisory signal (going off-hook) to the CO.

 loop-start interfaces: Devices, such as an analog telephones, that receive an analog electric current. For example, taking the receiver off-hook closes the current loop and initiates the calling process.

 LSI board: a Dialogic loop-start interface expansion board.

 MSI/SC board: a Dialogic Modular Station Interface board for connecting devices to station devices (phones), with conferencing support.

 Mu-law: (1) Pulse Code Modulation (PCM) algorithm used in digitizing telephone audio signals in T-1 areas. (2) The PCM coding and companding standard used in Japan and North America. See also A-law.

 NLP: Non Linear Processor. Operates on the output of the echo canceller to provide improved echo suppression as long as the echo reference signal contains a speech signals and the echo-carrying signal does not.

 off-hook: The state of a telephone station when the conductor loop between the station and the switch is closed and current is flowing. When a telephone handset is lifted from its cradle (or an equivalent condition occurs), the telephone line state is said to be off-hook. See also hook state.

 on-hook: Condition or state of a telephone line when a handset on the line is returned to its cradle (or an equivalent condition occurs). See also hook state.

 PC: Personal Computer. Refers to an IBM Personal Computer or compatible machine.

 PCM: See Pulse Code Modulation.

 polling: The process of repeatedly checking the status of a resource to determine when state changes occur.

 polling functions: Voice Library functions used to check the current status of a voice device. Polling functions are also used to examine the number and configuration of devices in the system and to detect when events occur on a device.

 Pulse Code Modulation (PCM): A technique used in DSP voice boards for reducing voice data storage requirements. Dialogic supports either mu-law PCM, which is used in North America and Japan, or A-law PCM, which is used in the rest of the world.

 resource: Functionality (e.g. voice-store-and-forward) that can be assigned to a call. Resources are shared when functionality is selectively assigned to a call and may be shared among multiple calls. Resources are dedicated when functionality is fixed to the one call.

 resource board: a Dialogic expansion board that needs a network or switching interface to provide a technology for processing telecommunications data in different forms, such as voice store-and-forward, speech recognition, fax, and text-to-speech.

 RFU: Reserved for future use.

 ring detect: The act of sensing that an incoming call is present by determining that the telephone switch is providing a ringing signal to the voice board.

 route: Assign a resource to a time slot.

 robbed-bit signaling: The type of signaling protocol implemented in areas using the T-1 telephony standard. In robbed-bit signaling, signaling information is carried in-band, within the 8-bit voice samples. These bits are later stripped away, or "robbed," to produce the signaling information for each of the 24 time slots.

 routing functions: Functions that assign analog and digital channels to specific SCbus time slots; these SCbus time slots can then be connected to transmit or listen to other SCbus time slots.

 sampling rate: Frequency with which a digitizer takes measurements of the analog voice signal.

 SCbus (Signal Computing Bus): A TDM (Time Division Multiplexed) bus that connects SCSA (Signal Computing System Architecture) resources. It allows audio, signaling, and control information to be transmitted and received among these resources. Also, a hardwired connection between Switch Handlers (SC2000 chips) on SCbus-based products for transmitting information over 1024 time slots to all devices connected to the SCbus.

 SCbus routing functions: Functions that enable an application to connect or disconnect (make or break) the receive (listen) channel of a device to or from an SCbus time slot.

 SCR: See Silence Compressed Record.

 SCSA: See Signal Computing System Architecture.

 Signal Computing System Architecture (SCSA): A Dialogic standard open development platform. An open hardware and software standard that incorporates virtually every other standard in PC-based switching. All signaling is out of band. In addition, SCSA offers time slot bundling and allows for scalability.

signaling insertion: The signaling information (on hook/off hook) associated with each channel is digitized, inserted into the bit stream of each time slot by the device driver, and transmitted across the bus to another resource device. The network interface device generates the outgoing signaling information.

 Silence Compressed Record (SCR): A recording that eliminates or limits the amount of silence in the recording without dropping the beginning of words that activate recording.

 silence threshold: The level that sets whether incoming data to the voice board is recognized as silence or nonsilence.

 SIT: (1) Standard Information Tones: tones sent out by a central office to indicate that the dialed call has been answered by the distant phone. (2) Special Information Tones: detection of a SIT sequence indicates an operator intercept or other problem in completing the call.

 solicited event: An expected event. It is specified using one of the device library's asynchronous functions. For example, for dx_play( ), the solicited event is "play complete."

 Special Information Tones: See SIT.

 speed and volume control: Voice software that contains functions and data structures to control the speed and volume of play on a channel. The end user controls the speed or volume of a message by entering a DTMF tone.

 speed and volume modification table: Each channel on a voice board has a table with 20 entries that allow for a maximum of 10 increases and decreases in speed or volume, and 1 "origin" entry that represents regular speed or volume.

 SpringWare: Software algorithms build into the downloadable firmware that provides the voice processing features available on all Dialogic voice boards.

 SRL: See Standard Runtime Library.

 Standard Attribute functions: Class of functions that take one input parameter (a valid Dialogic device handle) and return generic information about the device. For instance, Standard Attribute functions return IRQ and error information for all device types. Standard Attribute function names are case-sensitive and must be in capital letters. Standard Attribute functions for all Dialogic devices are contained in the Dialogic SRL. See Standard Runtime Library.

 Standard Information Tones: See SIT.

 Standard Runtime Library (SRL): A Dialogic software resource containing Event-Management and Standard Attribute functions and data structures used by all Dialogic devices, but which return data unique to the device. See the Standard Runtime Library Programmer's Guide for Linux.

 station device: Any analog telephone or telephony device (such as a telephone or headset) that uses a loop-start interface and connects to an MSI/SC board.

 string: An array of ASCII characters.

 subdevice: Any device that is a direct child of another device. Since "subdevice" describes a relationship between devices, a subdevice can be a device that is a direct child of another subdevice, as a channel is a child of a board.

SVP mode: The standard voice processing mode for a Dialogic voice channel, where all standard Dialogic voice channel features are enabled and the default echo cancellation is provided.

 synchronous function: Blocks program execution until a value is returned by the device. Also called a blocking function. See asynchronous function.

 System Release Development Package: The software and user documentation provided by Dialogic that is required to develop applications.

 T-1: A digital telephony format used in North America and Japan. In T-1, 24 voice conversations are time-division multiplexed into a single digital data stream containing 24 time slots. Signaling data are carried "in-band"; as all available time slots are used for conversations, signaling bits are substituted for voice bits in certain frames. Hardware at the receiving end must use the "robbed-bit" technique for extracting signaling information. T-1 carries data at the rate of 1.544 Mbps (DS-1 level).

tap: The echo tail length that the echo canceller handles in the ECR mode is 16 ms, also referred to as 128 tap. SVP mode echo cancellation utilizes a 48 tap (6 ms) echo canceller.

 TDM: See Time Division Multiplexing.

 termination condition: An event or condition which, when present, causes a process to stop.

 termination event: An event that is generated when an asynchronous function terminates. See asynchronous function.

 Time Division Multiplexing (TDM): A technique for transmitting multiple voice, data, or video signals simultaneously over the same transmission medium. TDM is a digital technique that interleaves groups of bits from each signal, one after another. Each group is assigned its own "time slot" and can be identified and extracted at the receiving end. See time slot.

 time slot: In a digital telephony environment, a normally continuous and individual communication (for example, someone speaking on a telephone) is (1) digitized, (2) broken up into pieces consisting of a fixed number of bits, (3) combined with pieces of other individual communications in a regularly repeating, timed sequence (multiplexed), and (4) transmitted serially over a single telephone line. Each individual pieced-together communication is called a time slot.

 time slot assignment: The ability to route the digital information contained in a time slot to a specific analog or digital channel on an expansion board. See device channel.

 training period: When used in reference to echo cancellation, the period after enabling echo cancellation during which the echo canceller develops an estimate of the echo component contained in the echo-carrying signal.

 Transaction Record feature: Permits recording two SCbus time slots from a single channel.

 Universal Dialogic Diagnostic program: Software diagnostic routines for testing board-level functions of Dialogic hardware.

 VFX: Any Dialogic combined voice, fax, and network interface board, such as the or VFX/40ESC.

 Voice hardware and software: Expansion boards and associated software that support voice processing.

 voice processing: Converting human voice into data that can be reconstructed and played back at a later time.

 Voice system: A combination of expansion boards and software that lets you develop and run voice processing applications.

 wink: In T-1 or E-1 systems, a signaling bit transition from on to off, or off to on, and back again to the original state. In T-1 systems, the wink signal can be transmitted on either the A or B signaling bit. In E-1 systems, the wink signal can be transmitted on either the A, B, C, or D signaling bit. Using either system, the choice of signaling bit and wink polarity (on-off-on or off-on-off hook) is configurable through DTI/xxx board download parameters.

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