Specifications

Chapter 3 Hardware
ReadyBoard 800 Reference Manual 39
Pin # Pin #
DB9
Signal Description
B16 8 CTS4*
RX4+
Clear To Send 4 – Indicates external serial communications device is ready to
receive data. Used as hardware handshake with RTS4 for low level flow
control.
RX4+ – If in RS485 or RS422 mode, this pin is Receive Data 4 +.
B17 4 DTR4* Data Terminal Ready 4 – Indicates Serial port 4 is powered, initialized, and
ready. Used as hardware handshake with DSR4 for overall readiness to
communicate.
B18 9 NC Not connected
B19 5 GND Ground
B20 NC NC Not connected
Notes: The shaded area denotes power or ground. RS232 signals are listed first followed by
RS485/RS422. The signals marked with * = Negative true logic.