A B C D E F G H I K L M N O P Q R S T U

Adaptive Answer

Allows a modem to discriminate between incoming fax or data calls, and answer appropriately.

Analog Signals

Continuous, varying waveforms such as the voice tones carried over phone lines.

ANSI

American National Standards Institute.

ASCII

American Standards Committee on Information Interchange. A standard used by IBM and compatibles to represent numbers and characters in binary form.

Asymmetric Data Rates

In asymmetric transmissions, the send and receive speeds may be different. Having the ability to have differing send and receive speeds allows you to take advantage of the line conditions, giving the best performance possible.

Asynchronous

In asynchronous transmissions, the length of time between transmitted characters is not uniform. The receiving modem must be signaled with Start and Stop bits as to when the data bits of a character begin and end.

Audio Frequencies

The frequencies which the human ear can detect (usually in the range of 15 to 20,000 Hertz). Only those from 300 to 3,000 Hertz are transmitted through the phone.

Audio, Full Duplex

An audio mode in which data can be sent and received at the same time. This mode must be supported by the audio hardware you are using. If you have the option of using it, you will probably find that it is more like natural conversation than using half duplex.

Audio, Half Duplex

An audio mode in which data can travel only in one direction at a time. This mode is determined by the kind of audio hardware you are using.

Authoring Systems

Authoring systems are used to create multimedia applications. They combine existing presentation information (texts, images and sound) and control the flow of these during the multimedia show. The dialogue with the user is controlled with this software. The individual information must have already been created and saved with special programs.

AUTOEXEC.BAT

A batch file that directs the activities performed by the computer during system startup.

AutoReliable Mode

The mode in which the modem makes the best possible connection, either Reliable or Normal.

Basic Input Output System (BIOS)

Program code in your PC’s ROM (Read-Only Memory) that provides the power-on self test and other operating functions for hardware such as disk drives, keyboard and monitor.

Baud Rate

The number of signal events per second occurring on a communications channel. Although not technically accurate, baud rate is commonly used to mean bit rate.

bps

bits per second

BIOS

See Basic Input/Output System (BIOS).

Bit Rate

The number of binary digits or bits transmitted per second.

Bits Per Second (bps)

The number of binary digits or bits transmitted per second. See also Bit Rate.

BLTZ

British Telecom Lempel-Ziv. Data compression protocol BTLZ connections require LAPM error correction.

Caller ID

Caller ID is a way for the recipient of a call to find out information on the caller. Between the first and second ring of an incoming call, the phone company sends information such as the phone number from which the call originated and a name (if any) associated with that number. A Caller ID box may also display the current date and time. Most phone companies offer this service.

Central Office (CO)

The place where your local phone company switches (or connects) all of your phone calls.

Class 1 (Fax)

A protocol for transmitting image data by a faxmodem and fax software. Class 1 fax software uses the computer's processor for handling all the encoding and decoding of the fax image.

Class 2 (Fax)

A protocol for transmitting image data by a faxmodem and fax software. The Class 2 fax protocol allows for some of the image encoding and decoding to be done by the fax modem's processor, thus saving time on your computer.

CNG Tone

The 1100Hz "beeping" tone a fax machine or faxmodem emits when calling out. When the receiving fax detects this tone, it automatically connects. It is this tone which allows a call-switching device to recognize an incoming fax call and transfer the call to the fax machine or modem. SupraSonic and SupraFAXModems using "Silent Answer" can recognize the CNG tone to receive a fax.

Command State

When your modem will accept AT commands. Synonym: Escape State. See also Online State.

Computer Rate

The rate at which a modem (DCE) and a computer (DTE) communicate. This is what changes when you set rate in your telecom software. Synonyms: Serial Port Rate, Modem-to-Computer Speed, DTE-DCE Rate, Communications Rate.

Config.sys

In MS-DOS, an ASCII text file in the root directory that contains configuration commands. MS-DOS consults this file at system startup.

Connection Rate

The rate at which modems communicate over a phone line. Synonyms: Transmission Speed, Line Speed, Carrier Rate, Modem-Modem Speed, DCE-DCE Rate.

CTS - Clear to Send Signal

See Hardware Handshaking.

Data Carrier Detect (DCD)

Signal from the modem or printer (DCE) to the DTE (your computer) to indicate that the modem is receiving a carrier signal from the modem at the remote end of the telephone circuit.

Data Compression

The process of reducing the size of data parcels to transmit more data in less time. See also Error Correction/Data Compression Protocols.

Data Terminal Ready (DTR)

Data Terminal Ready. Control signal from the DTE (computer) to the DCE (modem or printer) to indicate that the DTE is on and ready. Also used for hardware flow control.

DCE

Data Communications Equipment. Your modem. See also DTE.

Digital Signals

Discrete, uniform signals.

Direct Connection

Any standard modem connection, without error correction, data compression, or flow control. Computer rate must equal connection rate.

Distinctive Ring

Distinctive Ring is the ability to have multiple phone numbers on a single phone line. Each phone number has a unique ringing pattern. Most U.S. phone companies offer this service.

Driver

Part of a software program that interacts with a particular piece of equipment in your computer system (i.e. video boards, printers, and keyboards). Drivers are often loaded by your config.sys at system boot.

DTE

Data Terminal Equipment. Your computer or terminal.

DTR

See Data Terminal Ready.

Duplex

Indicates a communications channel capable of carrying signals in both directions.

Echo Canceling

A technique that causes modems to distinguish between actual signals and their echoes. Echoes are a serious problem on standard phone lines during high-speed data transmission.

Error Correction

The process of verifying the accuracy of transmitted data and retransmitting data that did not transfer successfully.

Error Correction/Data Compression Protocols

Protocols that increase the amount of data that can be transferred (data compression) and/.or improve the accuracy of transmissions (error correction). Some are MNP 2-5, V.42, V.42bis.

Fax Protocols

Protocols (defined by the international ITU-TSS standards committee) that serve as standards to let fax devices (faxmodems and fax machines) communicate at specific rates. Some are ITU-TSS V.17, ITU-TSS V.29, and ITU-TSS V.27ter.

Flow Control

A buffering system that optimizes throughput by allowing your computer and connection rates to be different.

Flash ROM

Allows you to upgrade your modem's ROM using software. SupraSonic, V.FC and V.34 SupraFAXModems have this feature.

Flow Control

A buffering system that optimizes throughput by allowing your computer and connection rates to be different.

Full Duplex

Signal flow in both directions.

Group 1, 2, and 3 Faxes

There are three internationally accepted specifications for fax equipment protocols. Most fax machines today are Group 3, as are SupraFAXModems. Many older fax machines do not support Group 3 faxing -- these machines typically won't be able to send to a Group 3 machine (or modem).

Half Duplex

Signal flow in both directions, but only one way at a time.

Hardware Handshaking (RTS/CTS)

A method of flow control used between the modem and the computer in which it is installed. When ready to send data, the computer will send a Request to Send (RTS) signal, to which the modem will reply with a Clear to Send (CTS) signal when it is ready to receive. CTS/RTS prevents the computer from sending more data than the modem can handle.

Initialization

In modems, the establishment of an active configuration that, in whole or in part, supersedes the factory configuration. By using an initialization string, you can configure the modem to work well with your communications program. See initialization string.

Initialization string

(Also referred to as init. string.) In modems, a group of AT commands issued to the modem by a communications program at the beginning of a communication session, that establishes an active configuration. Initialization strings enable communications programs to work smoothly with a variety of modems, and often you can choose an initialization string appropriate for your modem from a list provided in your communications program. See initialization.

Interrupt Request (IRQ)

Signal used by a device, such as a mouse, to inform the CPU that it is present and functioning.

Internet Service Provider (ISP)

A company that provides end users access to the Internet.

ITU (also ITU-T)

International Telecommunications Union (also known as ITU-T, International Telecommunications Union -Telecommunications section). An organization sponsored by the United Nations that sets standards for communications technology. In computers, ITU standards, such as the widely used V.32bis protocol that governs some high speed modem communications, enable modems from different manufacturers to communicate with one another. The ITU is the successor of the Comite Consultatif International Telephonique et Telegraphique (CCIT).

ITU-TSS V.42

The international standard protocols for error correction (MNP 2-4 and LAPM).

ITU-TSS V.42bis

The international standard protocols for error correction (MNP 2-4 and LAPM) and 4:1 data compression (BTLZ).

Jumper

A small plastic plug that fits over a pair of pins. When the plug straddles two pins it makes an electrical connection. The computer makes decisions based on whether the connection is made or not. A group of jumper pins is called a jumper block.

LAPM

Link Access Procedure for Modems. The error correction protocol preferred by the V.42bis modem protocol. BTLZ connections require LAPM error correction.

Local Echo

A modem feature that enables the modem to send copies of keyboard commands and transmitted data to the screen.

Local Modem

Your modem.

MNP

Microcom Networking Protocol. Protocols providing error correction (MNP 2-4, MNP 10) and 2:1 data compression (MNP 5).

Modem/Fax Modem

A modem (MODulator/DEModulator) is a device that can take computer data (a series of "1"s and "0"s) and convert it to tones that can be transmitted/received through a communications channel such as radio or telephone lines. Another modem at the other end can decode the tones back into the original data. Fax modems are modems that can also communicate with fax machines in addition to their data communications.

NVRAM

Nonvolatile Random Access Memory. User-programmable memory whose data is retained if the device is turned off.

Negotiation

The process where your modem and the remote modem determine what type of connection to make. Synonyms: Detection, Detection Phase.

Normal Connection

Same as a Direct connection, but with the addition of flow control, which allows the computer and connection rates to be different. A Normal connection does not support error correction or data compression.

Online State

When you can communicate with the remote computer. See also Command State.

Physical Protocols

Descriptions of actual electronic signals used to communicate over phone lines. For example, Bell 103/212A, ITU-TSS V.21/V.22/V.22bis/V.32/V.32bis. Synonym: Transmission Protocols.

Plug and Play

Plug and Play automatically manages the communication between the system and the new device. Windows™ 95 takes over all necessary work from loading the correct drivers to the most optimal connection between hardware and software.

Pulse Dialing

A means of telling the Central Office the number to be reached. Pulse dialing can be recognized by clicks, instead of beeps, when dialing. Not all phone systems support touch tone dialing; pulse dialing is the alternative. All Supra modems can use tone or pulse dialing.

Reliable Connection

A connection that uses one of the error correction or data compression protocols available.

Remote Modem

The modem to which you connect.

RAM

Ramdom Access Memory. See also NOVRAM.

ROM

Read Only Memory. The "brains" of your modem.

REN (Ringer Equivalence Number)

A number indicating the amount or quantity of ringers (or products) which may be connected to a single phone line and still ring. The total of all RENs connected to a single line may not exceed the value of five (5) or some or all of the ringers may not work. In some cases the maximum REN may be lower. Check with your local phone company if you are interested in the exact maximum REN for your line. Most Supra modems have a REN of 0.3 (REN is also called the "Load Number" in some cases).

RTS/CTS

Request to Send/Clear to Send. See Hardware Handshaking.

Silent Answer

Silent Answer allows your modem to "listen in" on an incoming phone call and determine whether or not the incoming call is a voice call or a fax call. After the call is answered by you or your answering machine, the modem listens for CNG tones. If they are detected, the modem will take the call. If they are not detected, the modem will ignore the call.

Synchronous

In synchronous transmission, blocks of data are sent at strictly timed intervals. The timing is uniform and no Start/Stop bits are required.

Terminal Stay Resident (TSR)

Programs that are run once then remain in memory in order to be activated by a sequence of key strokes or a hotkey. It is possible that a TSR may take up too much memory and cause conflicts with other programs.

Throughput

Effective transfer rate. Generally speaking, on a 14,400 bps connection, data will transfer at a maximum of 14,400 bps, so maximum throughput is 14,400 bps. But on a 14,400 bps V.42bis connection, where V.42bis compresses the data to one-fourth its size, throughput can be four times that of the non-V.42bis 14,400 bps connection, or 57,600 bps.

Tone Dialing

Commonly known as touch tone, tone dialing is a means of telling phone company equipment the number to be reached by means of differing tones for each number. Tone telephones have a dialing keypad, though some keypad phones use pulse dialing. All Supra modems can use either tone or pulse dialing.

Trunk Line

The path connecting your phone system to the phone company's Central Office.

TSR

See Terminate and Stay Resident.

UART