Omega Engineering OMB-NETSCAN 1500 User Manual page 127

NetScan to PC Connection
DB9 Male
Pin & Signal
2
3
5
7
8
NetScan Connection
DB9 Male
Pin & Signal
1
2
3
4
5
6
7
8
9
Serial Port Pin Connector Signals for RS-232/422 Applications
RxD- (Receive Data Negative) Input: This pin accepts serial data sent by an RS-232 or RS-422 device. The serial data
received is expected to match the word length, baud rate, stop bits, and parity configuration of the particular port. The signal is
low true.
RxD+ (Receive Data Positive) Input: This pin accepts serial data sent by an RS-422 device only. The signal is high true.
TxD- (Transmit Data Negative) Output: This pin transmits serial data to an RS-232 or RS-422 device. The serial data
received is sent with the word length, baud rate, stop bits, and parity configured for the particular port. The signal is low true.
TxD+ (Transmit Data Positive) Output: This pin transmits serial data to an RS-422 device only. The signal is high true.
CTS- (Clear To Send Negative) Input: CTS- input is used as a hardware handshake line to prevent NetScan from transmitting
serial data to an RS-232 or RS-422 device when it is not able to accept it. When RTS/CTS handshaking is selected, NetScan
will not transmit data out TxD- while this signal is un-asserted (low). If XON/XOFF or no handshaking is selected, the CTS-
line is ignored when transmitting data. The signal is low true.
CTS+ (Clear To Send Positive) Input: CTS+ input is used as a hardware handshake line to prevent NetScan from transmitting
serial data to an RS-422 device when it is not able to accept it. The signal is high true.
RTS- (Request To Send Negative) Output: RTS- output is used as a hardware handshake line to prevent an RS-232 or RS-422
device from transmitting serial data to NetScan when it is not able to accept it. When automatic RTS/CTS handshaking is
selected, NetScan will assert (high) the RTS- signal when greater than 4096 memory locations are available in its internal
buffers. If available memory drops below 4096 bytes, NetScan unasserts (low) the RTS- signal. The signal is low true.
RTS+ (Request To Send Positive) Output: RTS+ output is used as a hardware handshake line for an RS-422 device. The
signal is high true.
GND (Ground):
Hardware
(RS-232)
Cable DB9 Female
Wiring
Pin & Signal
⇐
RxD- 3
⇒
TxD- 2
⇔
GND 5
⇒
RTS- 8
⇐
CTS- 7
(RS-422)
Cable Wiring
⇐
RxD+
⇐
RxD-
⇒
TxD-
⇒
TxD+
⇔
GND
⇒
RTS+
⇒
RTS-
⇐
CTS-
⇐
CTS+
This signal sets the ground reference point for the other RS-232/RS-422 input and output signals.
TxD-
RxD-
GND
CTS-
RTS-
7-9