- COMSPHERE MODEMS INSTALLATION AND OPERATION MANUAL 392xPLUS, 3920PLUS, 3921PLUS

Glossary
Glossary-53920-A2-GN31-30 November 1996
EIA Electronic Industries Association. This organization provides standards for the data
communications industry.
EIA-232-D An Electronic Industries Association’s standard defining the 25-position interface
between data terminal equipment and data communications equipment.
EIA RS-366-A An Electronic Industries Association’s standard defining the 25-position interface
between data terminal equipment and data communications automatic calling equipment.
error control An algorithm used to correct data transmission errors.
escape sequence Default setting is +++. This sequence lets you switch your modem from Data mode to
Command mode.
extended circuit See extended network.
extended network The extension of a circuit where the tributary DCE is connected to a downstream
(extended) control DCE.
extended r
esult codes An asynchronous message (in either numbers or words) that includes VF data rate and
error control information the modem sends to the DTE after executing or trying to
execute a command.
fallback Retraining at a lower rate or speed.
FCC
Federal Communications Commission. Board of Commissioners that regulates all
interstate and foreign electrical communication systems that originate from the United
States.
FEC Forward Error Correction. A method of error control for data transmission where the
receiving device can detect and correct a character or block of code containing a
predetermined number of erroneous bits.
FEP Front-End Processor. A communications computer associated with a host computer that
manages the routing of data through the network.
full-duplex Simultaneous, two-way communications.
function key Any one of three keys on the DCP that allows you to select or increment an LCD entry.
Function keys are labeled F1, F2, and F3.
half-duplex Two-way data communications allowed in only one direction at a time.
handshaking
The exchange of predetermined codes and signals (tones) to establish a connection
between two modems.
HDLC High-Level Data Link Control. A communications protocol defined by the International
Standards Organization (ISO).
host A computer attached to a network that shares its information and devices with the rest of
the network.
Hz A unit of frequency (Hertz) that equals one cycle per second.