Datasheet

Copyright © 2011 Future Technology Devices International Limited 9
Document Reference No.: FT_000204
DB9-USB Datasheet
Version 2.1
Clearance No.: FTDI# 130
3 UART Connections
The PC compatible accepted electrical connections for male and female UART DB9 connectors are
illustrated in Figure 3.1 where the structure on the left is the top view of a male UART DB9 connector and
the structure on the right is the top view of a female UART DB9 connector.
Assuming a design follows these connection conventions, then an FTDI male or female DB9-USB
connector can be used to replace this UART DB9 connector to turn this port into an active USB interface.
GND
DTR
TXD
RXD
DCD
RI
CTS
RTS
DSR
1
2
3
4
5
9
8
7
6
GND
DTR
TXD
RXD
DCD
RI
CTS
RTS
DSR
1
2
3
4
5
6
7
8
9
MALE FEMALE
DTR
TXD
RXD
DCD
RI
CTS
RTS
DSR
DTR
TXD
RXD
DCD
RI
CTS
RTS
DSR
UART
Transceiver
PCB
PCB
DTE DCE
UART
Transceiver
GND
GND
Figure 3.1 – Male and Female DB9-USB internal connections (top view looking through the module)
Examples and signal directions are shown in Figure 3.2 and Figure 3.3