User manual

C H A P T E R 3 - S E R I A L I N T E R F A C E 5
R S 2 3 2
RS232 is a single-ended data transmission protocol. The RS232 signals are represented by voltage levels
with respect to a system common (power/logic ground). The “idle” state (MARK) has the signal level
negative with respect to common, and the “active” state (SPACE) has the signal level positive with respect to
common.
F i g u r e 3 : R S 2 3 2 D I P S w i t c h S e t t i n g s
ON ON
1 2 3 4 5 6 1 2 3 4 5 6
Normal RS232 Operation Forced 9600 Mode
T A B L E 3 : N L 9 0 0 P R O R S 2 3 2 P I N O U T
D B 9 P I N S I G N A L N A M E I / O D E S C R I P T I O N D E T A I L S
1 DCD O Data Carrier Detect Carrier Detect Signal.
Connects to DSR (pin 6).
9
5
6
1
Female DB9
2 TXD O Transmitted Data Serial Data from modem
to Host.
3 RXD I Received Data Serial Data from Host to
Modem.
4 DTR I Data Terminal Ready Used to determine if
modem is ready for
operation.
5 GND - Ground Ground
6 DSR O Data Set Ready Connects to DCD (pin 1).
7 RTS I Request To Send Provides RTS Flow Control
8 CTS 0 Clear To Send Provides CTS Flow Control
9 NC - No Connect No Connect