Specifications

Chapter 3 Hardware
LittleBoard 800 Reference Manual 25
Note: The shaded area denotes power or ground. Signals are listed in the table with RS232 first, followed
by RS485/RS422.
16 8 CTS4*
RX4+
Clear To Send 4 – Indicator to serial port 4 that 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 +.
17 4 DTR4* Data Terminal Ready 4 – Indicates this Serial port is powered,
initialized, and ready. Used as hardware handshake with DSR4 for
overall readiness to communicate.
18 9 NC Not connected (Ring Indicator 4)
19 5
GND Ground
20 NC NC Not connected
Table 3-6. Serial B Interface Pin/Signal Descriptions (J12)