ATEN US221A User manual

US221A / US421A
USB 2.0 Peripheral Switch
User Manual

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Compliance Statements
FEDERAL COMMUNICATIONS COMMISSION
INTERFERENCE STATEMENT
This equipment has been tested and found to comply with the
limits for a Class B digital service, pursuant to Part 15 of the
FCC rules These limits are designed to provide reasonable
protection against harmful interference in a residential
installation Any changes or modifications made to this
equipment may void the user’s authority to operate this
equipment This equipment generates, uses, and can radiate
radio frequency energy If not installed and used in accordance
with the instructions, may cause harmful interference to radio
communications However, there is no guarantee that
interference will not occur in a particular installation If this
equipment does cause harmful interference to radio or television
reception, which can be determined by turning the equipment off
and on, the user is encouraged to try to correct the interference
by one or more of the following measures:
Reorient or relocate the receiving antenna
Increase the separation between the equipment and receiver
Connect the equipment into an outlet on a circuit different
from that to which the receiver is connected
Consult the dealer or an experienced radio/TV technician
for help
The device complies with Part 15 of the FCC Rules Operation
is subject to the following two conditions: (1) this device may
not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause
undesired operation

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FCC Caution: Any changes or modifications not expressly
approved by the party responsible for compliance could void the
user's authority to operate this equipment
KCC Statement
RoHS
This product is RoHS compliant

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US221A / US421A
User Manual
Online Registration
You can register your product at our online support center:
Online Support
International
Telephone Support
For telephone support, call this number:
International http://support.aten.com
Email Support [e-mail]
Online
Support
Technical Support http://support.aten.com
Troubleshooting
ocumentation
Software Updates
http://www.aten.com
International 886-2-8692-6959
China 86-400-810-0-810
Japan 81-3-5615-5811
Korea 82-2-467-6789
North America 1-888-999-ATEN ext 4988
1-949-428-1111

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North America
Email Support [e-mail]
Online
Technical
Support
Troubleshooting
ocumentation
Software
Updates
http://www.aten-usa.com/support
Telephone Support 1-888-999-ATEN ext 4988
1-949-428-1111

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Package Contents
Check to make sure that all the components are in working order.
If you encounter any problem, please contact your dealer.
The US221A / US421A USB 2.0 Peripheral Switch package
contains the following items:
 1 2-port (US221A) or 4-port (US421A) USB 2.0 Peripheral
Switch
 1 1.8 m USB Type A to USB Type B Cable
 1 User Instructions*
Read this manual thoroughly and follow the installation and
operation procedures carefully to prevent any damage to the unit
or any connected devices.
*The product may be updated, with features and functions
added, improved or removed since the release of this manual.
For an up-to-date US221A / US421A documentation, visit http:/
/www.aten.com/global/en/

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Overview
The US221A / US421A is a 2/4-port USB 2.0 Peripheral Switch
that allows up to 2/4 computers to share the use of a single USB
peripheral device (such as a printer, scanner, mass storage drive,
etc.*) on a one-at-a-time basis.
The peripheral focus can be given to a computer manually by
using pushbuttons on the switch or by using the software-based
configuration utility. In addition, the US221A / US421A has a new
Auto Switch function that stores commands sent to the USB
peripheral device to be processed on a first-come, first-served
basis, meaning that a print server is not required.
Compatible with both Windows and Mac, and with multifunction
printer support, the US221A / US421A is the ideal way to share
the latest USB 2.0 peripherals in a multimedia SOHO
environment.
Note: The US221A / US421A does not support a USB hub
peripheral device.

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Features
 Enables two (US221A) or four (US421A) computers to share
a single USB peripheral device
 Simple port selection via pushbuttons or easy-to-use
configuration utility
 Auto Switch function – no need for a separate print server
 USB 2.0 compliant
 Supports transfer rates up to 480 Mbps
 Multiplatform support – Windows and Mac
 LE indicators display port focus
 Overcurrent protection
 Bus-powered
 Hot pluggable
 Buzzer indicates switching between computers
 Supports multifunction printers

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System Requirements
Computers
The following equipment must be installed on each computer that
is to be connected to the system:
 USB host controller
Cables
 USB to USB cables to connect the computers to the
peripheral device.
Note: Only one USB Type A to USB Type B cable is provided
in the US221A / US421A package. You will need to
purchase an additional USB Type A to USB Type B
cables for each computer you wish to connect to the
US221A / US421A.
Operating Systems
Supported operating systems are shown in the table, below:
OS Version
Windows 2000, XP, 2003, 2008, Vista
Mac OS X 10.4.5, 10.5

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Components
Top View
1
2
3
2
1
3
4
4

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Rear View
No Component Description
1 lock LE Lights orange to show that the US221A /
US421A is locked.
2 port selection
pushbutton(s)
Pressing a port selection pushbutton brings
control to the computer attached to its
corresponding port. See Manual Operation –
Pushbutton, page 14 for further details.
3 port selected
LE s
Lights green to show that the computer
attached to its corresponding port has control.
4 beeper on/off
switch (on side)
Use this recessed switch to turn the US221A /
US421A’s beeper on or off.
5 USB Type-B
computer port
Your computers plug into these ports. See
Installation, page 12 for further details.
6 USB Type-A
peripheral port
Your USB 2.0 peripheral device plugs into this
port.
5
6
5
6

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Installation
The US221A / US421A USB 2.0 Peripheral Switch provides 2/4
USB Type-B ports for computers to connect to, and one USB
Type-A port for the peripheral device (multifunction printer,
scanner, mass storage device, etc.) that the computers will
share.
To install the US221A / US421A, do the following:
1. Use your USB device's USB cable to connect it to the
US221A / US421A's USB Type-A port.
2. Plug the USB Type-B connector of the USB Type-A to USB
Type-B cable provided with the US221A / US421A package
into any available port on the US221A / US421A.
3. Plug the USB Type-A connector into the computer’s USB host
port.
Repeat steps 2 and 3 for any other computers you are installing.
Note: Only one USB Type-A to USB Type-B cable is provided in
the US221A / US421A package. You will need to
purchase an additional USB Type-A to USB Type-B
cables for each computer you wish to connect to the
US221A / US421A.
1. Make sure that the power to any device that you
connect to the installation has been turned off and
that all devices are properly grounded.

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1
2
3

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Manual Operation – Pushbutton
Note: Manual operation and the software-based configuration
utility operate independently; commands from one will not
override the other.
US221A
To toggle the USB peripheral focus between the two computers,
press the port selection pushbutton (located on the top of the
unit). The selected port LE flashes and the unit beeps. When
the flashing stops and the LE becomes steady (in about four
seconds), that port has the peripheral focus.
US421A
To switch the peripheral focus to another port, press the
pushbutton that corresponds to that port. The selected port LE
flashes and the unit beeps. When the flashing stops and the LE
becomes steady (in about four seconds), that port has the
peripheral focus.
Lock/Unlock Peripheral Focus
To lock the peripheral focus on a certain computer, press and
hold the pushbutton that corresponds to that port for two
seconds, or until the orange LE lights up.
To unlock the peripheral focus, press and hold the pushbutton
that corresponds to that port for one second, or until the orange
LE turns off.

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Software Operation
Installing the Configuration Utility
The US221A / US421A has a software-based configuration utility
that can be used to configure the US221A / US421A's settings,
such as the Auto Switch function, Manual Switch and Release
reminder, and sound effects. The utility can also be used to lock
and unlock control of the US221A / US421A.
Note: Microsoft Windows users should login as an administrator
to install and launch the US221A / US421A software.
To install the configuration utility, do the following:
Note: 1. Below examples are based on a Windows 10 operating
system.
2. The screens shown in this section are for reference
only. The wording and layout of the actual screens put
up by the Software Installation Utility may vary slightly
from these examples.
1. From a computer that is connected to the US221A / US421A
using USB Type-A to USB Type-B cable, go to our Aten
Support & ownload → ownloads site and choose the
model name that relates to your device (US221A / US421A)
to get a list of available Software Installation Packages.
2. Choose the Software Installation Package you want to install
(usually the most recent), and download it to your computer.

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3. Extract and open the downloaded software installation
package file, right click on the Setup icon, and select Run as
administrator as shown in the picture below.
4. The Software Installation Utility welcome screen appears, and
select Next.

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5. To choose a destination location, click Change, or click Next to
continue.
6. A confirmation screen appears, click Next to begin the
upgrade.

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7. After the upgrade has completed, you will be asked to restart
the PC. Click Yes to restart the PC now, or click No to restart
the PC later, then click Finish to exit the Software Installation
Utility.
8. When the installation completes, an icon labeled USB 2.0
Peripheral Switch Utility appears on your desktop and
another icon appears in your system tray.
The icon on your system tray displays in four colors to indicate
the US221A / US421A’s status, as shown in the following table:
Color Status
Green Locked on local computer
Yellow Connected to local computer
Red Peripheral device not connected
Grey isconnected or busy

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Installing the Configuration Utility on Mac
The US221A / US421A has a software-based configuration utility
that can be used to configure the US221A / US421A's settings,
such as the Auto Switch function, Manual Switch and Release
reminder, and sound effects. The utility can also be used to lock
and unlock control of the US221A / US421A.
Note: Mac users should login as an administrator to install and
launch the US221A / US421A software.
To install the configuration utility, do the following:
Note: The screens shown in this section are for reference only.
The wording and layout of the actual screens put up by the
Software Installation Utility may vary slightly from these
examples.
1. From a computer that is connected to the US221A / US421A
using USB Type-A to USB Type-B cable, go to our Aten
Support & ownload → ownloads site and choose the
model name that relates to your device (US221A / US421A)
to get a list of available Software Installation Packages.
2. Choose the Software Installation Package you want to install
(usually the most recent), and download it to your computer.
3. ouble-click to extract the downloaded software installation
package file.

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4. A .dmg file appears on your desktop. ouble-click it to run the
installation.
5. The installation page appears. Simply click and drag the AT N
USB 2.0 Peripheral Switch Utility icon to Applications folder.