USB to Serial Converters Manual
Version 2.1
Document Reference No.: CP_000032 Clearance No.: CP#022
Copyright © Connective Peripherals Pte Ltd
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This converter is also provided with adapter cables which convert the RJ45 into a DB-9 connector. This
connector uses the same pin-out as in Table 11 above but the Ring Indicator signal is not available as it
is not brought out on the RJ45 connector.
Figure 11 -RJ45 Connector Pin Numbers
Pin Number
Pin Type
Description
1
Output
RTS = Request To Send
2
Output
DTR = Data Terminal Ready
3
Ground
GND = RS232 signal ground
4
Output
TXD = Transmit Data
5
Input
RXD = Receive Data
6
Input
DCD = Data Carrier Detect
7
Input
DSR = Data Set Ready
8
Input
CTS = Clear To Send
Table 13 - RS-232 Pin-Out for RJ45 Connector
Terminal Block RS232 Pin-Out (ES-U-2101-MB)
On the ES-U-2101-MB (version B) an RS232 mode has been added. On the terminal block, only the TxD
and RxD signals are available in addition to the GND and an optional 5V output. The other terminals must
be left unconnected.
Pin Number
Pin Type
Description
1
Leave un-connected
2
Input
RXD = Receive Data
3
Output
TXD = Transmit Data
4
Leave un-connected
5
Power
For ES-U-2101-MB, pin 5 is optional 5VDC output
6
Ground
GND = Signal ground
Table 14 - RS-232 Pin-Out for Terminal Block on ES-U-2101-MB
5.2
RS-422 Signal Pin-out
DB-9 Male connector
Table 15 shows the RS-422 pin-out of the DB-9 Male connector
Pin Number
Pin Type
Description
1
Output
TxD- = Transmit data, negative polarity
2
Output
TxD+ = Transmit data, positive polarity
3
Input
RxD+ = Receive data, positive polarity
4
Input
RxD- = Receive data, negative polarity
5
Ground
GND = Signal ground
6
Output
RTS- = Request to send, negative polarity
7
Output
RTS+ = Request to send, positive polarity
8
Input
CTS+ = Clear to send, positive polarity
9
Input
CTS- = Clear to send, negative polarity
1 2 3 4 5 6 7
8
