B&B Electronics USOTL4 User manual
USOTL4-1405 - 1/2
© 2004 by B&B Electronics. All rights reserved.
pn 5253-r4
B&B ELECTRONICS
Model USOTL4
Connect and Isolate an RS-485/RS-
422 Network to the USB Port CE
The USOTL4 is a USB (Universal Serial Bus) port to 2 or 4 wire isolated RS-485/422 converter. This converter requires
no PCI/ISA slots or IRQs. Simply plug the converter into an available USB port on your computer or hub. Windows will
configure the converter as an additional COM port, compatible with your Windows applications. The serial port side can
be set up for an RS-422 or RS-485 network. A pair of LEDs shows when RS-485/422 data is being received or
transmitted. The USB side permits quick setup. Just plug in the USOTL4 and Windows will install the drivers and set up
the converter. USB bus supplies power so no separate power supply is needed. 2000 volt RMS of isolation.
Installation for Windows
#1. Plug the USOTL4 into an available USB port on your
computer or connected hub. The screen above appears,
telling you that there is a new device plugged into the USB
bus. Click on the Next> button.
#2. The screen above appears. Make sure Search for the
best driver for your device is selected. Then select the
Next> button.
International Headquarters: 707 Dayton Road PO Box 1040 Ottawa, IL 61350 USA
European Headquarters: Westlink Commercial Park Oranmore Co. Galway Ireland
PRODUCT INFORMATION
#4. The screen above appears. Make sure Model
USOTL4 (B&B’s USB to Isolated RS-485) is listed as
the device. Then select the Next> button.
#3. The screen above appears. Make sure CD-ROM drive
is selected. Insert the USOTL4 Driver CD into the CD-
ROM drive. Then select the Next> button.
USOTL4-1405 - 2/2
© 2004 by B&B Electronics. All rights reserved.
pn 5253-r4
B&B ELECTRONICS
DECLARATION OF CONFORMITY
Manufacturer’s Name: B&B Electronics Manufacturing Company
Manufacturer’s Address: P.O. Box 1040
707 Dayton Road
Ottawa, IL 61350 USA
Model Numbers: USOTL4
Description: Optically Isolated USB to RS-422/485 Converter
Type: Light industrial equipment
Application of Council Directive: 89/336/EEC
Standards: EN 55022
EN 61000-6-1
EN 61000 (-4-2, -4-3, -4-4, -4-5, -4-6, -4-8, -4-11)
Robert M. Paratore, Director of Engineering
#6. You will also need to continue to install the serial
port the same as installing the converter. Click the Next
button followed by the Finish button. It will take a
couple seconds for the serial port to be installed.
USOTL4 RS-422
Device
TDA(-)
TDB(+)
RDA(-)
RDB(+)
GND
RDA(-)
RDB(+)
TDA(-)
TDB(+)
GND
USOTL4 in a four-wire set-up
with all switches in the OFF position.
RS-485
Network
USOTL4
RS-485
Device
TDA(-)
RDA(-)
GND
TDB(+)
RDB(+)
Data (B)
Data (A)
Data (B)
Data (A)
GND
USOTL4 in a two-wire set-up
with all switches in the ON position.
RS-485 Control
No special software is required to control the RS-485 receiver
or transmit line driver. The driver is automatically enabled
during each byte transmitted in RS-485 mode. The
transmitter is always enabled in RS-422 mode. The receiver
is tri-stated during each byte transmitted in the echo-off
mode. The receiver is always enabled in the echo-on mode.
There are 4.7k Ohm pull-up/pull-down resistors on the RDA
and RDB lines. A termination resistor may be added to R16 if
needed. See B&B’s RS-422/RS-485 Application Note
(available on our website or by mail) for more information on
termination and DC biasing of an RS-485 network.
Dip Switch Set-up
Dip switches allow the module to be configured for two-wire
or four-wire, RS-422 or RS-485 modes. In two-wire mode the
TDA (-) and RDA (-) are tied together and so are TDB (+) and
RDB (+), making multi-dropping this converter into an existing
network easy.
Switch OFF ON
One TD always enabled
(TD 422) TD only enabled during data
transmission. (TD 485)
Two RD always enabled
(ECHO ON) RD disabled during data
transmission. (OFF)
Three Four-wire mode
(4-Wire) Two-wire mode
(2-Wire)
Four Four-wire mode
(4-Wire) Two-wire mode
(2-Wire)
Specifications
Dimensions: 2.7 x 5.1 x 0.9 in (6.9 x 13.0 x 2.3 cm)
Temperature Range: 0 to 70oC (32 to 158oF)
RS-485/422 Baud Rate: Up to 460.8 kbps
USB Baud Rate: High speed device
USB Power: Low power device (draws < 100mA)
Operating System: Windows 98/SE, 2000, ME, XP
Accessories: Driver CD
Isolation: 2000 V RMS
#5. The screen above will appear. Click the Finish
b
utton to com
p
lete the installation.
International Headquarters: 707 Dayton Road PO Box 1040 Ottawa, IL 61350 USA
European Headquarters: Westlink Commercial Park Oranmore Co. Galway Ireland
PRODUCT INFORMATION
