半双工

Duplex \Du"plex\, a. [L., fr. duo two + plicare to fold. See
{Two}, and {Complex}.]
1. Double; twofold.

2. (Computers) organized so that data may be transmitted in
two opposite directions over the same channel; -- of
communications channels, such as data transfer lines
between computers.
[PJC]

{Duplex escapement}, a peculiar kind of watch escapement, in
which the scape-wheel has two sets of teeth. See
{Escapement}.

{Duplex lathe}, one for turning off, screwing, and surfacing,
by means of two cutting tools, on opposite sides of the
piece operated upon.

{Duplex pumping engine}, a steam pump in which two steam
cylinders are placed side by side, one operating the
valves of the other.

{Duplex querela} [L., double complaint] (Eccl. Law), a
complaint in the nature of an appeal from the ordinary to
his immediate superior, as from a bishop to an archbishop.
--Mozley & W.

{Duplex telegraphy}, a system of telegraphy for sending two
messages over the same wire simultaneously.

{Duplex watch}, one with a duplex escapement.

{half duplex} (Computers)
(a) arranged so that the information may be transmitted in
both directions, but only in one direction at a time;
-- of communications channels between computers;
contrasted with {full duplex(a)}.
(b) arranged so that the information transmitted to the
remote computer also appears on the local terminal; --
of communications channels between computers;
contrasted with {full duplex(b)}.

{full duplex}, (Computers)
(a) arranged so that the information may be transmitted in
both directions simultaneously; -- of communications
channels between computers; contrasted with {half
duplex(a)}.
(b) arranged so that the information transmitted to the
remote computer does not appear on the local terminal;
-- of communications channels between computers;
contrasted with {half duplex(b)}.