USRobotics V.34 user manual Eia

COURIER HIGH SPEED MODEMS

Dedicated Line

A user-installed telephone line used to connect a specified num- ber of computers or terminals within a limited area, for example, one building. The line is a cable rather than a public- access telephone line. The communications channel may also be referred to as nonswitched because calls do not go through telephone company switching equipment.

Default

Any setting assumed, at startup or reset, by the computer's soft- ware and attached devices, and operational until changed by the user.

Digital Loopback

A test that checks the modem's RS-232 interface and the cable that connects the terminal or computer and the modem. The modem receives data (in the form of digital signals) from the computer or terminal, and immediately returns the data to the screen for verification.

Digital Signals

Discrete, uniform signals. In this manual, the term refers to the binary digits 0 and 1.

Duplex

Indicates a communications channel capable of carrying signals in both directions. See Half Duplex, Full Duplex.

EIA

Electronic Industries Association, which defines electronic stan- dards in the U.S.

Equalization

A compensation circuit designed into modems to counteract certain distortions introduced by the telephone channel. Two types are used: fixed (compromise) equalizers and those that adapt to channel conditions. U.S. Robotics high speed modems use adaptive equalization.

J-6 Glossary