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© Sealevel Systems, Inc.
SeaI/OUSBSERIAL | SL9177 04/2022
Connector Pin Assignments (RJ45)
–
RS-232/485 VersaCom
The SeaI/O 647U and 687U utilize the RS-232/485 VersaCom connector pin out. Integrated status LEDs on each
RJ45 serial port display transmit and receive data activity.
Name
Pin #
Mode
D+
RS-485 Data +
1
RTS
Request To Send
2
Output
TX
Transmit Data
3
Output
GND
Ground
4
PWR
Power Output
5
RX
Receive Data
6
Input
CTS
Clear To Send
7
Input
D-
RS-485 Data
–
8
DCD, DSR, and RI are inputs that are not brought out on the RJ45 connector. DSR and DCD are biased
active, and RI is biased inactive.
Interface Selection
With the unique VersaCom multi-interface connector design, both RS-232 and two-wire RS-485 signals are
always present and active on the RJ45 connectors. Simply select the appropriate pin out for RS-232 or two-wire
RS-485 on each individual port. The unused interface on each connector should be left unconnected. All inputs
have appropriate biasing to keep them in an inactive state. If the unused interface pins are connected to a cable,
the outputs will attempt to drive the lines while the inputs will attempt to interpret any voltage on the line as data,
which can limit cable length and may result in communication failures.
