Computer Interfacing

Serial versus parallel

Idle

A LSB

1

v

Start

bit

Date

~V

i bits : 7-bit ASCII

code for Έ'

HSB A A

-^

1

1

Parity Stop

bit bit

(odd

parity)

Idle

Figure

5.1 A

serial data packet

for the

character

E

(ASCII code

= 45

H

). Odd parity

is

being used

streams must be identical at both the sending and re-

ceiving ends. There are a number of standard frequencies

which are actually termed Baud rates, these being gen-

erally understood to mean the number of bits of data

transmitted per second. This is not always strictly true

but is close enough for our purposes. The range of Baud

rates extends from about 50 to 19,200. Lower speeds are

for slow electromechanica ...