Westermo RM-455U-D - Manual (Page 25)

455U-D Radio Modem User Manual
Page 26 © May 2010
DCE HOST
DB9
MALE
MODEM
DB9
MALE
RD
TD
SG
RTS
CTS
DSR
DTR
DCD
RD
TD
SG
RTS
CTS
DSR
DTR
DCD
2
5
7
8
6
4
1
3
2
5
7
8
6
4
1
3
DCE HOST MODEM
DB9
MALE
DB9
FEMALE
RD
TD
SG
RTS
CTS
DSR
DTR
DCD
RD
TD
SG
RTS
CTS
DSR
DTR
DCD
2
5
7
8
6
4
1
3
2
5
7
8
6
4
1
3
2.4 Serial Connections
2.4.1 RS232 Serial Port
The serial port is a 9 pin DB9 female and provides for
connection to a host device as well as a PC terminal for
configuration, field testing and for factory testing.
Communication is via standard RS232 signals. The 455U-D
is configured as DCE equipment with the pinout detailed
below. Hardware handshaking using the CTS/RTS lines is
provided. The CTS/RTS lines can be configured to reflect
the status of the local unit’s input buffer. The 455U-D
supports XON/XOFF flow control.
Example cable drawings for connection to a DTE host (a PC) or another DCE host (or modem) is
detailed below.
DB9 Connector Pinout
Pin Name Direction Function
1 DCD Out
Data carrier detect –
- driven when link is established in Acknowledged mode
- driven when module is online in unacknowledged mode
2 RD Out Transmit Data from modem – Serial Data Output
3 TD In Receive Data into modem – Serial Data Input
4 DTR In
Data Terminal Ready - DTR can be configured to initiate low
power mode, or to force a link disconnection (“hang up” in
Acknowledged mode.
5 SG Signal Ground
6 DSR Out Data Set Ready - always high when unit is powered on.
7 RTS In Request to Send - hardware flow control configurable
8 CTS Out Clear to send - hardware flow control configurable
9 RI Out
Ring indicator - indicates another module is attempting to connect
in Acknowledged mode.