Apollo ECM-3612, User Manual

Page: 31 / 104

User’s Manual
ECM-3612 User’s Manual 31
2.3.7 Serial Port 2 Connector in RS-232/422/485 Mode (CM4)
2.3.7.1 Serial Port 2 Connector in RS-232 Mode
Signal PIN PIN Signal
DCD 1 2 RxD
TxD 3 4 DTR
GND 5 6 DSR
RTS 7 8 CTS
RI 9 10 NC
2.3.7.1.1 Signal Description – Serial Port 2 Connector in RS-232 Mode (CM4)
Signal Signal Description
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.