ASIX UCAB232 User manual

UCAB232
Reference Manual
RS‑232 interface for USB

ASIX s.r.o.
Staropramenna 4
150 00 Prague
Czech Republic
www.asix.net
[e-mail]
[e-mail]
ASIX s.r.o. reserves the right to make changes to this document, the
latest version of which can be found on the Internet.
ASIX s.r.o. renounces responsibility for any damage caused by the use
of ASIX s.r.o. products.
© Copyright by ASIX s.r.o.

Table of Contents
UCAB232 4
1
4
1.1 Package Contents
4
1.2 Features
4
1.3 Quick Start
4Windows1.3.1
4Linux1.3.2
4
1.4 How to use theUCAB232 converter
5RS‑232 interface1.4.1
Data rate 5
5LED indicators1.4.2
5Standby1.4.3
5Resistance to external influences1.4.4
6
1.5 Technical Specification
6Absolute Maximum Ratings1.5.1
6Operating Specifications1.5.2
DRIVERS 7
2
7
2.1 Drivers Installation
7Windows operation system2.1.1
Windows7 and newer 7
Windows XP 7
7Linux operation system2.1.2
7
2.2 Drivers Update
7Windows 72.2.1
8Windows XP2.2.2
8
2.3 Troubleshooting and Special
Requirements
8High demands on time response2.3.1
9
2.4 User OEM Application
Document history 10
3

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1
UCAB232
Thank you for buying our product. If you have any
question, please do not hesitate to contact our technical
support.
1.1 Package Contents
UCAB232 Converter
CD-ROM with Drivers and User Guide
Leaflet
1.2 Features
Full RS-232 implementation
High communication speed
250kBaud guaranteed
more than 500kBaud typically
Powered from USB, no additional power supply needed
Standard 9-pin SubD connector
Receive buffer 384Byte
Transmit buffer 128Byte
Full hardware flow control using RTS/CTS, DTR/DSR/
DCD, hardware assisted XON/XOFF
USB 2.0 compatible, Full speed
Possibility to customize VID, PID for OEM products
Drivers for Windows and Linux
for OEM application, proprietary ID can be used
Low power consumption (USB suspend mode)
Cable length 1m
1.3 Quick Start
It is necessary to install drivers before first use.
1.3.1 Windows
Please insert USB plug connector of your UCAB232i
converter into PC USB port. The drivers are installed
automatically from Microsoft update server.
1.3.2 Linux
LINUX kernel 2.6.31 or newer includes required drivers
and there is no need to install them.
1.4 How to use
theUCAB232 converter
UCAB232 adds an RS-232 interface to a USB equipped
computer.
The converter is designated for all standard RS-232
devices (mouses, modems, data terminals, barcode
readers, serial printers).
After installation the drivers a new COM port device will
be ready to use by software applications in standard
fashion (e.g. Win32 API function calls).
It is possible to set up the UCAB232i COM port number in
the control panels.

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1.4.1 RS‑232 interface
Fig.2: DB9, pins
UCAB232 provides all RS-232 signals.
The description of RS-232 signals is given bellow in the
table:
Pi
n
Name
I/O
Description
1
DCD
IN
Data Carrier Detect
2
RD
IN
Receive Data
3
TD
OUT
Transmit Data
4
DTR
OUT
Data Terminal Ready
5
SG
PWR
Signal Ground
6
DSR
IN
Data Set Ready
7
RTS
OUT
Request to Send
8
CTS
IN
Clear to Send
9
RI
IN
Ring Indicator
Table 1: RS-232 signals description
Data rate
The guaranteed data rate is within the range of 300Baud
to 250kBaud,
TheUCAB232 converter allows to communicate typically
over 500kBaud. However, this data rate is not
guaranteed and could depend on temperature and an
external signal quality.
1.4.2 LED indicators
UCAB232 is equipped with two LED indicators.
Red LED: data are being sent from PC to a RS-232
connected device
Green LED: data are being sent from a RS-232 connected
device to PC
1.4.3 Standby
The UCAB232 converter fully supports PC standby mode
(sleep).
1.4.4 Resistance to
external influences
Theoperating temperature range is between 0°C to
+70°C.
The converter complies the IP20 specification.

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1.5 Technical Specification
1.5.1 Absolute Maximum
Ratings
Operating temperature
min. 0°C
max.+70 °C
Storage temperature
min. -55°C
max.+85 °C
Active USB current
max. 100mA
All input voltages to signal
ground
±25V
All output voltages to
signal ground
±13V
ESD immunity
±8kV contact HBM
±6kV air HBM
±15kV Human Body Model
Electric Field Immunity
3V / m
Table 2: Absolute Maximum Ratings
1.5.2 Operating
Specifications
Minimum data rate
300Baud
Maximum data rate
220kBaud guaranteed,
500kBaud typically
Input Treshold Low RS-232
min. 0.8V, typ. 1.5V
Input Treshold High RS-232
max. 2.4V, typ. 1.8V
Output voltage Swing1
min. ±5V, typ. ±5.4V
Short-circuit tolerance
No limit
Short-circuit current
maximum ±60mA
Operating system
Windows2 32/ 64-bit
Linux 1.5.0 32/64-bit
MAC OS 10 32/64-bit
WindowsCE
3
RS-232
full implementation
RS-232 connector
DB9
USB 1.1 a 2.0 compatibility
yes, 12Mbps (Full Speed)
USB connector
A type
Length of USB cable
1m
Transmit indicator
red LED
Receive indicator
green LED
Table 3: Operating Range
1 Outputs Loaded with 3kΩ.
2 Windows8, Windows7, WindowsServer,
WindowsServer2003, WindowsVista, WindowsXP.
Compatible with 32/64bit. version.
3 WindowsMobile2003, WindowsMobile2003SE,
WindowsMobile5, WindowsMobile6,
WindowsMobile6.1,WindowsMobile6.5

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2
DRIVERS
In this chapter, we will discuss drivers installation, drivers
updating and specific COM port setting requirements.
2.1 Drivers Installation
2.1.1 Windows operation
system
The driver installation runs automatically from Windows
Update. In case the computer is not on the internet, it is
possible to download the drivers from FTDI corp.
(www.ftdichip.com) and install them manually in the
device manager.
Notes:
It is possible to set up the converter COM port number in
the control panels.
Windows7 and newer
With Windows7 operation system drivers are installed
automatically from Microsoft update server every time
the UCAB232 converter has been inserted into USB port.
The successful installation is indicated by a message.
Fig.3: Drivers installation
Windows XP
When a new device has been detected by operating
system it is necessary to agree searching the drivers on
the Windows Update and continue with automatic
installation. The installation continues then in two steps,
first the converter driver and then the virtual COM port
driver are being installed. After the installation the
UCAB232 converter is ready for use.
2.1.2 Linux operation
system
LINUX kernel 2.6.31 or newer includes required drivers
and there is no need to install them. If you use operation
system based on that kernel, the UCAB232 converter will
simply start to work when it has been inserted into USB
port.
2.2 Drivers Update
UCAB232 is based on FTDI IC, FTDI Chip company
www.ftdichip.com steadily updates drivers for their ICs.
To keep your drivers updated follow this chapter.
2.2.1 Windows 7
Signed drivers are automatically downloaded from
Microsoft update server when the UCAB232 converter has
been inserted into USB port. Every time operation system

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is being updated, drivers are kept updated, too.
Another way how to update drivers in Windows7 is very
complicated or rather impossible.
2.2.2 Windows XP
Windows XP drivers are stable for a long time, thus there
is usually no reason for update them with the exception
that another software application using FTDI IC on the
same PC requires it. In that case, drivers are available for
download at www.ftdichip.com
2.3 Troubleshooting and
Special Requirements
Some of applications have special requirements for
RS-232 communication, which demand particular correct
settings of the UCAB232 converter.
If there is any difficulty in communication between the
RS-232 connected device and PC try options listed below.
Red LED indicates transmitting, it can serve as acheckon
that software application sends data to a correct PC port.
In other case, please check the COM port number in
software application and the assigned COM port number
by operating system.
The COM port number can be found and/or changed in
Control Panel/Device Manager/Ports.
If the RS-232 connected device does not reply (LED
indicator does not blink) although software application
sends data, it is possible that there is not correctly set
„Baud rate“ (communication speed), „Data bits“, „Parity“,
„Stop bits“ or „Flow control“. Please check that the
settings meets specification of the RS-232 connected
device.
2.3.1 High demands on
time response
If the connected device replies (LED indicator blinks) but
software application still does not receive data it is
possible that the software application has high demands
on time response.
The way of communication through USB is very different
than communication through RS-232. USB uses packets
of 64B size. Furthermore, a RS-232 device device can
receive only on PC request. Hence it is almost impossible
to assure time response lower than about 1ms.
Time response settings can be done in ControlPanel/
Device/Manager/Ports/.../PortSettings/ /Latency Timer. In
case of troubles set this number to 1ms.
Fig.4: COM port Enhanced Settings

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2.4 User OEM Application
The $UCAB converter allows user to design an OEM
application after which the converter is found and listed
as a customer hardware.
For doing this, it is necessary to modify drivers,
particularly, to change the UCAB232 converter VID and
PID, which are originally set to 0403 / 6001, to customer
numbers and write these numbers with the FT_PROG
utility to the converter EEPROM.
Before a modification of EEPROM it is advisable to create
a backup of EEPROM in case there is any trouble with VID/
PID identifiers.
For smooth installation of modified driver on Windows7 a
newer the digital sign of the driver will be requested. For
more information about driver sign see the web pages of
Microsoft corporation.

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3
Document history
Document
revision
Modifications made
2014-05-30
Newly created document.
2014-06-11
Drivers section updated