ROBO-503/ROBO-503N
ROBO-503/ROBO-503N User’s Manual
39
3.7.33 DB9 Serial Port 1 Connector in RS-232 Mode (CN14)
Signal
PIN
Signal
GND
5
9
RI
DTR
4
8
CTS
TxD
3
7
RTS
RxD
2
6
DSR
DCD
1
3.7.34 Signal Description – Serial Port 1 – COM1 in RS-232 Mode (CN14)
TxD
Serial output. This signal sends serial data to the communication link. The signal is set to a
marking state on hardware reset when the transmitter is empty or when loop mode operation is
initiated.
RxD
Serial input. This signal receives serial data from the communication link.
DTR
Data Terminal Ready. This signal indicates to the modem or data set that the on-board UART is
ready to establish a communication link.
DSR
Data Set Ready. This signal indicates that the modem or data set is ready to establish a
communication link.
RTS
Request To Send. This signal indicates to the modem or data set that the on-board UART is
ready to exchange data.
CTS
Clear To Send. This signal indicates that the modem or data set is ready to exchange data.
DCD
Data Carrier Detect. This signal indicates that the modem or data set has detected the data
carrier.
RI
Ring Indicator. This signal indicates that the modem has received a telephone ringing signal.