Cambridge O Level Computer Science · Syllabus 2210 · Data Transmission
Parallel Transmission
What is Parallel Transmission?
Parallel transmission is a method of data transmission in which several bits are sent at the same time, each along its own separate data line.
This definition is part of the Data Transmission chapter in Cambridge O Level Computer Science.
Parallel Transmission in context
Serial and parallel answer one question: how many bits travel at once, and on how many data lines? In serial transmission, bits are sent one after another along a single data line. In parallel transmission, several bits are sent at the same time, each along its own data line. Neither is simply “better”: parallel moves more bits per unit of time over a short link, but over distance the separate lines lose their alignment and interfere with one another, which is why long links are almost always serial.
Questions students ask about Parallel Transmission
What is the difference between serial and parallel transmission?
In serial transmission, bits are sent one after another along a single data line. In parallel transmission, several bits are sent at the same time, each along its own separate data line. Parallel can move more bits per unit of time over a short link, but over a longer distance the separate lines lose their timing alignment and interfere with one another, which is why long-distance links, such as USB, almost always use serial transmission instead.