Technical description – Impulse 7404 User Manual
Page 11
Technical
Description
Sealevel Systems COMM+4.PCI Page
8
Technical Description
The Sealevel Systems COMM+4.PCI provides a PCI interface adapter with 4
RS-232/422/485 asynchronous serial ports for industrial automation and control
applications.
The COMM+4.PCI utilizes the 16C864 UART. This chip features
programmable baud rates, data format, interrupt control and industry leading
128-byte transmit and receive FIFOs.
Connector Pin Assignments
RS-422/485 (DB 9 Male)
Signal Name Pin
#
Mode
GND Ground
5
TX +
Transmit Data Positive
4
Output
TX-
Transmit Data Negative
3
Output
RTS+
Request To Send Positive
6
Output
RTS-
Request To Send Negative
7
Output
RX+
Receive Data Positive
1
Input
RX-
Receive Data Negative
2
Input
CTS+
Clear To Send Positive
9
Input
CTS-
Clear To Send Negative
8
Input
RS-232 (DB-9
Male)
Signal Name
Pin
# Mode
GND Ground
5
TD Transmit
Data
3 Output
RTS
Request To Send
7
Output
DTR
Data Terminal Ready
4
Output
RD Receive
Data
2 Input
CTS
Clear To Send
8
Input
DSR
Data Set Ready
6
Input
DCD
Data Carrier Detect
1
Input
RI Ring
Indicator
9
Input
Technical Note: Please terminate any control signals that are not going to be
used. The most common way to do this is connect RTS to CTS and RI. Also,
connect DCD to DTR and DSR. Terminating these pins, if not used, will help
ensure you get the best performance from your adapter.