Appendix a, System do® device rs232 port configurations, System do – Xylem SDI-12 Data Logger iLink User Manual
Page 63: Device rs232 port configurations
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APPENDIX A
System DO
®
Device RS232 Port Configurations
The 9 pin RS232 Port on the System DO
®
devices (DS-CPU3, DS-12840i, DS-4483 and DS-COM9) can
be used for connection to a PC or a radio fitted with a RS232 data port. It is a DTE configured port. Its
pinouts are shown below together with the standard null modem cable connections. The port may be
configured for a standard range of baud rates and character framing types via the user program. The
RS232 port device is a MAX-202 or MAX-222 type device and these meet the standard EIA-232D and
V.28/V.24 interface specifications.
DB9 Pin
Function
Pin Specification
Pin 1
Not used
Pin 2
Receive Data in (RXD)
Min ± 3V
Max
±30V
Pin 3
Transmit Data out (TXD)
Min ± 5V loaded with 3k to GND
Typ ± 8V
Pin 4
Data Terminal Ready out (this is linked active permanently to +12V via 10k resistor)
Pin 5
Ground
Pin 6
Not used
Pin 7
Request to Send out (RTS)
Min ± 5V loaded with 3k to GND
Typ ± 8V
Pin 8
Clear to Send in (CTS)
Min ± 3V
Max
±30V
Pin 9
Not used
The standard cable to connect an IBM PC compatible computer to these ports should be wired as shown.
The data rate is typically 9600bits/sec.
Device RS232 Port
Computer RS232 Port
DB9 Type
DB25 Type
Pin 2 (RXD)------------------------------------------------------- Pin 3 (TXD)
Pin 2 (TXD)
Pin 3 (TXD) ------------------------------------------------------- Pin 2 (RXD)
Pin 3 (RXD)
Pin 5 (GND) ------------------------------------------------------ Pin 5 (GND)
Pin 7 (GND)
Pin 7 (RTS) ------------------------------------------------------- Pin 8 (CTS)
Pin 5 (CTS)
Pin 8 (CTS) ------------------------------------------------------- Pin 7 (RTS)
Pin 4 (RTS)
Note: The RTS/CTS lines are not required unless the port is used in a way that
requires the handshaking lines externally e.g. when connected to a serial printer
and the port is used in ASCII mode.