Datasheet

Copyright © 2010 Future Technology Devices International Limited 6
Document Reference No.: FT_000148
USB-COM232-PLUS4 Datasheet
Version 1.2
Clearance No.: FTDI# 97
2 Installation
2.1 Example Applications and Configurations
2.1.1 Wiring
Insert the A-plug into an available USB Host or Hub port. Insert the miniB-plug into the miniB-receptacle
on the USB-COM232-PLUS4.
RS232 cables have followed a standard 9-pin configuration on a D-sub connector since the mid 1980s.
The USB-COM232-PLUS4 follows this standard as a Data Terminal Equipment (DTE) device. If the RS232
equipment being connected is a Data Communication Equipment (DCE) device, it’s typical that a straight-
through cable can be used.
DTE Pin Number
Signal Name
DCE Pin Number
1
DCD = Data Carrier Detect
1
2
RXD = Receive Data
2
3
TXD = Transmit Data
3
4
DTR = Data Terminal Ready
4
5
GND = RS232 signal ground
5
6
DSR = Data Set Ready
6
7
RTS = Request To Send
7
8
CTS = Clear To Send
8
9
RI – Ring Indicator
9
Table 2.1 – RS232 DTE to DCE connection with straight-through cable
If the USB-COM232-PLUS4 is connected to another DTE device, a serial “null-modem” cable is required. A
null-modem cable handles connecting output signals to the corresponding input signals on the other end.
Table 2.3 shows a typical null-modem cable. Note that RI and DCD are not always used.
DTE Pin Number
Signal Name
DTE Pin Number
2
RXD = Receive Data
3
3
TXD = Transmit Data
2
4
DTR = Data Terminal Ready
6
5
GND = RS232 signal ground
5
6
DSR = Data Set Ready
4
7
RTS = Request To Send
8
8
CTS = Clear To Send
7
Table 2.2 – RS232 DTE to DTE connection with null-modem cable
Some serial devices may require certain handshake signals be connected. Refer to your device manual
for cabling details.