| asynchronous communication
This term describes how your computer
uses a modem to connect with other computers. Back in the days of
teletypes and dumb terminals, computers sent data synchronously--they
operated using a shared timer that marked the transmission of each
character. This didn't work very efficiently for large blocks of data over
phone lines, however. So modern modems use asynchronous rules: instead of
synching up to a time signal to mark a character, transmitting computers
use a start bit, a stop bit, and an optional error-checking parity bit to
indicate to receiving computers the boundary of each character. (The term
is a bit of a misnomer, though, since all modems synch up with one another
before they transmit data.) |