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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5
Connector Pinout Information
This section shows the connector pinouts used on the ES-U-xxxx-x converters.
5.1
RS-232 Signal Pin-out
DB-9 Male connector
The RS232 ports are configured as Data Terminal Equipment (DTE), with a 9-contact D-Sub Pin
connector. Pin assignments are according to TIA/EIA-574 which formally defines the assignments for a
COM port found on many personal computers.
Figure 10 - DB-9 Male Connector Pin Numbers
Pin Number
Pin Type
Description
1
Input
DCD = Data Carrier Detect
2
Input
RXD = Receive Data
3
Output
TXD = Transmit Data
4
Output
DTR = Data Terminal Ready
5
Ground
GND = RS232 signal ground
6
Input
DSR = Data Set Ready
7
Output
RTS = Request To Send
8
Input
CTS = Clear To Send
9
Input
RI = Ring Indicator
Shield
Case Ground
Drain = typically connected to the host PC case
Table 11 - RS-232 Pin-Out for DB-9 connector
RS232 DB-9 Pin-Out (ES-U-2101-MB)
The ES-U-2101-MB has a reduced set of signals which are shown in Table 12. It includes the most used
signals TxD/RxD/RTS/CTS/GND.
Note that the other pins of the connector must be left unconnected as indicated below.
Pin Number
Pin Type
Description
1
Leave un-connected
2
Input
RXD = Receive Data
3
Output
TXD = Transmit Data
4
Leave un-connected
5
Ground
GND = RS232 signal ground
6
Leave un-connected
7
Output
RTS = Request To Send
8
Input
CTS = Clear To Send
9
Leave un-connected
Table 12 - RS-232 Pin-Out for DB-9 connector on ES-U-2101-MB
RJ45 connector
Table 13 shows the pin-out of the RJ45 connectors used on the ES-U-1032-RM converter.
