Serial data transmission in which information can be transmitted in two directions, but only one
direction at a time, is called:
A.
Synchronized
B.
Full-duplex
C.
Simplex
D.
Half-duplex
Explanation:
The time required to switch transmission directions in a half-duplex line is called the turnaround
time. * Answer simplex refers to communication that takes place in one direction only. * Answer
Synchronized is a distracter. * Full-duplex can transmit and receive information in both directions
simultaneously. The transmissions can be asynchronous or synchronous. In asynchronous
transmission, a start bit is used to indicate the beginning of transmission. The start bit is followed by
data bits and, then, by one or two stop bits to indicate the end of the transmission. Since start and
stop bits are sent with every unit of data, the actual data transmission rate is lower since these
overhead bits are used for synchronization and do not carry information. In this mode, data is sent
only when it is available and the data is not transmitted continuously. In synchronous transmission,
the transmitter and receiver have synchronized clocks and the data is sent in a continuous stream.
The clocks are synchronized by using transitions in the data and, therefore, start and stop bits are
not required for each unit of data sent.