RS232 Port
PSI BOX Reference
when it it is unable to receive any more data. The sending
device reads DTR on its CTS and DCD pins. It should
stop sending when CTS goes false.
4)
Connect the PSI RTS pin 4, to the PC DSR line, pin 6.
Also, connect up the PC RTS line, pin 4, to the PSI DSR
line, pin 6.
This RTS line is used to let the other device know that it
is ready for data exchange.
Connecting To A Modem.
______________________
_
If you are connecting a MODEM to the PSI BOX then
you will not need a cross over cable and a straight through cable
connecting pins 1-8 and 20 is all that is required.
Figure 5-7. The RS232 Port Pin Outs.
________________________________
PIN
SIGNAL
DIRECTION
___
______
_________
1
GROUND
N/A
2
TxD TRANSMITTED DATA
OUTPUT FROM PSI BOX
3
RXD RECEIVED DATA
INPUT TO PSI BOX
4
RTS REQUEST TO SEND
OUTPUT FROM PSI BOX
5
CTS CLEAR TO SEND
INPUT TO PSI BOX
6
DSR DATA SET READY
INPUT TO PSI BOX
7
GROUND
N/A
8
DCD DATA CARRIER DETECT
INPUT TO PSI BOX
20
DTR DATA TERMINAL READY
OUTPUT FROM PSI BOX
9-19
NO CONNECTION
21-25
NO CONNECTION
Chapter 5
Page 45
