SFRA45 User Manual
6-9
6.7
RS232 connections
The RS232 port on SFRA45 uses the same pinout as a
standard 9 pin serial port on a PC or laptop (9-pin male ‘D’
type).
Pin
Function
Direction
1
DCD
in (+ weak pull up)
2
RX data
in
3
TX data
out
4
DTR
out
5
GND
6
DSR
not used
7
RTS
out
8
CTS
in
9
RI
not used
The SFRA45 will only transmit when CTS (pin 8) is
asserted, and can only receive if DCD (pin 1) is asserted.
KinetiQ constantly asserts (+12V) DTR (pin 4) so this pin
can be connected to any unwanted modem control inputs
to force operation without handshaking. KinetiQ has a
weak pull up on pin 1 as many null modem cables leave it
open circuit. In electrically noisy environments, this pin
should be driven or connected to pin 4.
To connect the SFRA45 to a PC, use a 9 pin female to 9 pin
female null modem cable:
1 & 6
-
4
2
-
3
3
-
2
4
-
1 & 6
5
-
5
7
-
8
8
-
7
