USRobotics V.34 user manual Appendix J. Glossary

COURIER HIGH SPEED MODEMS

APPENDIX J. GLOSSARY

Cross-references in the following definitions are printed in boldface.

Adaptive Speed Leveling (ASL)

Courier V.32 bis and V.32 terbo modems detect improved line conditions and shift upward again to the next higher speed. The modems at both ends of the connection adapt independently, each detecting and adjusting to line conditions. ASL keeps the modems online, always operating at the highest possible speed, and constantly ensuring data integrity.

Analog Loopback

A modem self-test in which data from the keyboard is sent to the modem's transmitter, modulated into analog form, looped back to the receiver, demodulated into digital form, and returned to the screen for verification.

Analog Signals

Continuous, varying waveforms such as the voice tones carried over phone lines. Contrast with digital signals.

Answer Mode

A state in which the modem transmits at the predefined high frequency of the communications channel and receives at the low frequency. The transmit/receive frequencies are the re- verse of the calling modem which is in Originate mode.

Application (application program)

A computer program designed to perform a specific function, such as a word processor or a spreadsheet.

ARQ

Automatic Repeat Request. A general term for error control protocols which feature error detection and automatic retrans- mission of defective blocks of data. See HST, MNP, and V.42.

Glossary J-1