User Manual

GLOSSARY
116
full duplex
Signals can flow in both directions at the same
time over one line. In microcomputer
communications, may refer to the suppression
of the online local echo.
half duplex
Signals can flow in both directions, but only
one way at a time. In microcomputer
communications, may refer to activation of the
online 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 cycles per second.
ITU-T
An international organization 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.
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.