User's Manual

GLOSSARY

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234839, Revision 2.2

Frame

See Block.

Frame Time

Specifies the maximum length of each packet frame (larger the time, the more information that can be contained within the

frame).

Forward Error Correction (FEC)

Technique of transmitting additional information with the original data so that if small errors are detected the correct

information can be recreated by the receiving end without requiring a retransmission.

Full Duplex

Data transmission, which allows data to flow in two directions at the same time.

Gateway

An electronic connection that joins similar networks together, for example IP to IP. Generally transparent to the user.

Half Duplex

Data transmission in which data may flow in either direction at one time, but not both directions simultaneously.

Transmission direction is alternatively switched to allow two-way flow of data.

Handshake

A predetermined interchange of signals between two devices to establish conditions for a transfer of data.

Hang-up

Termination of the Communications Link. As with a normal phone call, the phone must be hung-up so that you can call and

receive other calls.

Hang-up on DTR

Only available with the Main Port. If activated, will terminate the Communication Link when the Data Terminal Ready pin is

low.

Hardware

The electronic or electro-mechanical devices in a computer system as opposed to the programs or software.

Hardware Handshaking

The use of special RS-232 signals to halt or commence the flow of data between two computers or terminals, between

computers and modems or between facsimile machines. See also Software Handshaking, RTS and CTS.

Hayes

Company that designed the AT commands.

Hertz (Hz)

Unit of frequency, one cycle per second.

Hopping Pattern

Pattern to which the modem jumps through the frequency spectrum as it transmits and receives information. There are 32

hopping patterns available, all modems that are to communicate with each other must have the same hopping pattern.

Host Computer

A computer that manages information for many terminals. A host computer may be mainframe, minicomputer or a

microcomputer.

Input

Information transferred into a computer from some external source, such as the keyboard, a disk drive, a modem or a

scanner. Also, the act or process of transferring such information.