User`s guide

GLOSSARY
53
LAPM
Link Access Procedure for Modems is an error-
control protocol defined in ITU-T
Recommendation 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 En.
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.
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).
online fall back/fall forward
A feature that allows a high-speed, error-control
modem to monitor line quality and fall back to the
next lower speed in a defined range if line quality
diminishes. As line conditions improve, the modem
switches up to the next higher speed.
originate mode
The mode used by your modem when initiating an
outgoing call to a destination modem. The transmit/
receive frequencies are the reverse of the called
modem, which is in answer mode.