US Robotics 56K Series Manual page 53

frame
A data communications term for a
block of data with header and trailer
information attached. The added
information usually includes a frame
number, block size data, error-check
codes, and Start/End indicators.
full duplex
These signals will 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
These signals will 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 is 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.22bis.
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