Computer Interfacing

Serial versus parallel

+12V --

(Logic 0)

0V —

-12V

(Logic 1) Starts

Data

J | Stop

Parity

Figure

5.7

RS232C voltage levels

This interface is sometimes referred to under the dual

reference EIA232/V.24. The latter is actually a European

specification under the auspices of the CCITT and, for

practical purposes, may be considered as virtually in-

terchangeable with EIA232.

Data codes

Probably the best known code is the one referred to as

ASCII, which stands for American standard code for in-

formation interchange. Each of the alphanumeric and

Enable

Serial

IN

1/4 LM1488

^\

\ <

f-

j400pF

Line

1/4 LM1489

H

U^

\Λ

550pF

.

Serial

—► Data

OUT

Figure

5.8

Usin ...