US Robotics 56K Series Manual page 54

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
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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 some modems, it
includes four stored phone numbers and
the modem settings.