US Robotics Sportster Flash x2 User Manual page 42

Half Duplex
Signal flow in both directions, but only one way at a time. In
microcomputer communications, may refer to activation of the on-line
Local Echo, which causes the modem to send a copy of the
transmitted data to the screen of the sending computer.
Hz
Hertz, a frequency measurement unit used internationally to indicate
one cycle per second.
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, 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 Hn.
MNP
Microcom Networking Protocol, 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 errored 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.
38 Sportster Flash x2 - User's Guide