3Com 1.024.1644-00 manual Local echo, Modem, Nonvolatile memory Nvram, OFF/ON hook

Glossary

ITU-T

An international organisation that defines standards for telegraphic and telephone equipment. For example, the Bell 212A standard for 1200 bps communication in North America is observed internationally as ITU-T V.22. For 2400 bps communication, most U.S. manufacturers observe V.22 bis. The initials ITU-T represent the ‘International Telecommunications Union - Telecommunications sector’.

LAPM

Link Access Procedure for Modems is an error-control protocol defined in ITU-TRecommendation V.42. Like the MNP protocols, LAPM uses cyclic redundancy checking (CRC) and retransmission of corrupted data (ARQ) to ensure data reliability.

local echo

A modem feature that enables the modem to display keyboard commands and transmitted data on the screen. See command Hn.

MNP

Microcom Networking Protocol is an error-control protocol developed by Microcom, Inc., and now in the public domain. There are several different MNP protocols, but the most commonly used one ensures error-free transmission through error detection (CRC) and retransmission of erred frames.

modem

A device that transmits/receives computer data through a communications channel such as radio or telephone lines. It also changes signals received from the phone line back to digital signals before passing them to the receiving computer.

nonvolatile memory (NVRAM)

A user-programmable random access memory which retains data when power is turned off. On the 3Com U.S. Robotics modem it includes four stored phone numbers and the modem settings.

OFF/ON hook

Modem operations that are the equivalent of manually lifting a phone receiver (taking it off-hook) and replacing it (going on-hook).

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