3Com 56K manual Glossary

8GLOSSARY

local echo A modem feature that enables the modem to send copies of key-board commands and transmitted data to the screen. When the modem is in Command mode (not online to another system) the local echo is invoked through the ATE1 command. The command causes the modem to display your typed commands. When the modem is online to another system, the local echo is invoked through the ATF0 command. This command causes the modem to display the data it transmits to the remote system.

MB Megabyte. One million bytes.

Microcom An asynchronous error control protocol developed by Microcom, Inc. Networking Protocol and now in the public domain. The protocol ensures error-free

(MNP) transmission through error detection (CRC) and retransmission of errored frames. 3Com modems use MNP Levels 1-4 and Level 5 data compression. MNP Levels 1-4 have been incorporated into ITU-T Recommendation V.42. Compare HST.

MI/MIC Mode Indicate/Mode Indicate Common. Also called fixed or manual originate. Used when equipment other than the modem does the dialing. In such installations, the modem does not respond to AT commands, but when taken off hook immediately goes into call originate mode.

MNP See Microcom Networking Protocol.

modem A device that transmits/receives computer data through a communications channel such as radio or telephone lines. The Business Modem is a telephone channel modem that modulates, or transforms, digital signals from a computer into the analog form that can be carried successfully on a phone line. It also demodulates signals received from the phone line back to digital signals before passing them to the receiving computer.

Nonvolatile Random User-programmable random access memory whose data is retained Access Memory when modem power is turned off. Used in modems to store a

(NVRAM) user-defined default configuration loaded into random access memory (RAM) at power on.

NVRAM See Non-volatile Random Access Memory.

online fallback A feature that allows high speed error-control modems to monitor line quality and fall back to the next lower speed if line quality degrades. The modems fall forward as line quality improves.