The data transmission method in which data is sent continuously and doesn’t use either an internal
clocking source or start/stop bits for timing is known as:

A.
Asynchronous

B.
Pleisiochronous

C.
Synchronous

D.
Isochronous

Explanation:
Isochronous data is synchronous data transmitting without a clocking source, with the bits sent
continuously and no start or stop bits. All bits are of equal importance and are anticipated to occur
at regular time intervals. * asynchronous, is a data transmission method using a start bit at the
beginning of the data value, and a stop bit at the end of the value. * synchronous, is a
messageframed transmission method that uses clocking pulses to match the speed of the data
transmission. * pleisiochronous, is a transmission method that uses more than one timing source,
sometimes running at different speeds. This method may require master and slave clock devices.
Source: Communications Systems and Networks by Ray Horak (M&T Books, 2000).