USB to RS232 DB9/DB25 Serial Adapter Cable - M/M

Add an RS232 serial port to a notebook or desktop computer with this Plug-and Play USB adapter cable

Product ID: ICUSB232DB25

5 stars (1 reviews) |
  • USB powered; No external power adapters needed
  • Supports serial transfer speeds up to 250Kbps
  • Includes a DB9 to DB25 pin adapter for 25-pin RS232 serial communication
Your price
¥2,329 JPY excl.
¥2,562 JPY incl.

The ICUSB232DB25 USB to RS232 DB9/DB25 Serial Adapter Cable (M/M) lets you connect 9-pin (DB9) or 25-pin (DB25) RS232 serial devices to your laptop or desktop computer through a USB port, as though the computer offered an onboard serial port. The integrated 3-foot (0.9 meter) cable allows it to be connected directly from the serial device to the computer without requiring additional cables.

A cost-effective solution that bridges the compatibility gap between modern computers and legacy serial peripherals, this high quality USB/RS232 Serial Adapter cable ships with a DB-9 to DB-25 adapter for connection to varied serial equipment.

Backed by a StarTech.com 2-year warranty and free lifetime technical support.

Applications

  • Ideal for connecting serial devices to laptops or tablet PCs through the USB port
  • Connect to and monitor/control industrial sensors
  • Connect bar code scanners and other serial devices to a USB port
  • Connect a serial modem, digital camera, or PDA with serial sync to your PC's USB port
  • Connect to automotive ODB/ODBII sensor adapters that use serial connectivity

The StarTech.com Advantage

  • This versatile device ships with a 9-pin connector, and a 25-pin RS232 adapter for a variety of connection options
  • Integrated 3ft cable allows you to connect directly to your serial devices
  • Plug-and-Play/Hot-swap support enables you to add and remove this adapter without having to reboot the computer

Partner Numbers

  • SYNNEX Japan ZU2006X
  • UPC 065030840453

Compatibility

  • Windows 8 logo
  • Windows 7 logo
  • Windows Server 2012 logo
  • Linux logo
  • Windows 10 logo
  • Mac OS X El Capitan (10.11) logo
  • macOS Sierra (10.12) logo
  • Windows Server 2016 logo
  • macOS High Sierra (10.13) logo
  • macOS Mojave (10.14) logo
  • Windows Server 2019 logo
  • macOS Catalina (10.15) logo
  • macOS Big Sur (11.0) logo
Windows® PocketPC 2003 / 2000, Windows Mobile 5/6, CE 4.2/5.2, Embedded System 2009, XP Embedded, POS Ready 2009, 98SE, 2000, ME, XP, Vista, 7, 8, 8.1, 10
Windows Server® 2003, 2008 R2, 2012, 2016, 2019
macOS 10.6 to 10.15, 11.0
Linux 2.4.x to 4.11.x LTS Versions only

Specifications

Warranty Information Warranty 2 Years
Connector(s) 1 - Connector Type(s) USB Type-A (4 pin) USB 2.0
1 - External Ports DB-25 (25 pin, D-Sub)
DB-9 (9 pin, D-Sub)
Environmental Operating Temperature 0°C to 70°C (32°F to 158°F)
Storage Temperature -40°C to 85°C (-40°F to 185°F)
Humidity 5~85% RH
Hardware Ports 1
Interface Serial
Bus Type USB 2.0
Port Style Cable Adapters
Chipset ID Prolific - PL2303
Packaging Information Package Height 1.3 in [32 mm]
Package Length 6.8 in [17.2 cm]
Shipping (Package) Weight 5.0 oz [143 g]
Package Width 5.6 in [14.3 cm]
Performance Serial Protocol RS-232
Max Baud Rate 230.4 Kbps
Data Bits 4, 5, 6, 7, 8
FIFO 512 Bytes
Flow Control None, Xon/ Xoff, Hardware
Parity None, Even, Odd, Mark, Space
Stop Bits 1, 1.5, 2
Physical Characteristics Weight of Product 2.6 oz [75 g]
Color Gray
Material Plastic
Cable Length 36.0 in [91.5 cm]
Product Length 36.0 in [91.5 cm]
Software OS Compatibility Windows® PocketPC 2003 / 2000, Windows Mobile 5/6, CE 4.2/5.2, Embedded System 2009, XP Embedded, POS Ready 2009, 98SE, 2000, ME, XP, Vista, 7, 8, 8.1, 10
Windows Server® 2003, 2008 R2, 2012, 2016, 2019
macOS 10.6 to 10.15, 11.0
Linux 2.4.x to 4.11.x LTS Versions only
Microsoft WHQL Certified Yes
What's in the Box 1 - Included in Package 3ft USB to RS232 Cable
DB9 to DB25 Serial Adapter
Driver CD
Manual

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Driver(s):

Manual(s):

Datasheet

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Frequently Asked Questions

Installation

Starting in High Sierra 10.13, macOS enforces stricter security policies than previous revisions. As a result of these changes, software packages, like those used in this installation, will need to be allowed within the macOS Security and Privacy settings, immediately after the software has been installed, in order for the device to operate.

To allow the software, follow these steps after you've completed installation on your Mac:

  1. Open System Preferences.
  2. Open Security & Privacy.
  3. Click the Allow button near the bottom of the General tab.

Note: The option to allow the software will be available within the Security & Privacy settings for 30 minutes. If the software is not allowed within that time frame, the software must be reinstalled in order for macOS to grant the opportunity to allow it again.

Some driver installation packages may require you to disable driver signature enforcement in Windows 8, which will allow unsigned driver packages to be installed on your system.

Note: Before you continue, save any open documents and close all open programs.

To disable driver signature enforcement, complete the following:

  1. Press the Windows key + C.
  2. Click Settings > Change PC Settings.
  3. In the left pane, click General.
  4. In the right pane, under Advanced startup, click Restart now.

When your system finishes restarting, complete the following:

  1. Click Troubleshoot > Advanced options > Startup Settings > Restart.
  2. Press 7.

When your computer restarts, driver signature enforcement will be disabled and you can install your drivers.

Note: When you restart your computer after you install your drivers, driver signature enforcement will be enabled again. This does not prevent your newly installed drivers from working, but does prevent any other unsigned drivers from being installed until driver signature enforcement is disabled.

Some driver installation packages may require you to disable driver signature enforcement in Windows 8.1, which will allow unsigned driver packages to be installed on your system.

Note: Before you continue, save any open documents and close all open programs.

To disable driver signature enforcement, complete the following:

  1. Press the Windows key + C.
  2. Click Settings > Change PC Settings.
  3. In the left pane, click Update & Recovery.
  4. In the left pane, click Recovery.
  5. Under Advanced startup, click Restart now.

When your system finishes restarting, complete the following:

  1. Click Troubleshoot > Advanced options > Startup Settings > Restart.
  2. Press 7.

When your computer restarts, driver signature enforcement will be disabled and you can install your drivers.

Note: When you restart your computer after you install your drivers, driver signature enforcement will be enabled again. This does not prevent your newly installed drivers from working, but does prevent any other unsigned drivers from being installed until driver signature enforcement is disabled.­­­­­­­

You may need to disable Driver Signature Enforcement in Windows 10 to use some driver installation packages. When you disable this feature, you can install unsigned driver packages on your computer.

Note: Before you continue, save any open documents and close all of your programs. You will need to restart your computer to disable Driver Signature Enforcement.

To disable Driver Signature Enforcement, complete the following:

  1. Click the Windows icon in the taskbar.
  2. Click Power.
  3. Press and hold the Shift key and click Restart.

After your computer finishes restarting, complete the following:

  1. Click Troubleshoot Advanced Options Startup Settings > Restart.
  2. Press 7.   

When your computer finishes restarting, Driver Signature Enforcement will be disabled and you can install the drivers.

Note: When you restart your computer after you install your drivers, driver signature enforcement will be enabled again. This does not prevent your newly installed drivers from working, but does prevent any other unsigned drivers from being installed until driver signature enforcement is disabled.­­­­­­­

Prior to installing this device, ensure that your operating system is up to date (for example, you have installed the most recent service pack).

To install the driver:

  1. Download the latest drivers from the StarTech.com website (http://www.startech.com/Support). You can find the part number and product ID on the product’s packaging.

Note: Windows will typically save the files to the Downloads folder that is associated with your user account (for example, C:\Users\your_name\Downloads).

  1. Once the download is complete, right-click the zip folder that you downloaded, select Extract All, and follow the on-screen instructions.
  2. In the list of extracted files, right-click the Setup.exe file and select Run as Administrator.

Note: If the Run as Administrator option is not available, you might be attempting to run the installer from within the zipped file. Extract the files using the instructions in Step 2.

  1. Follow the on-screen prompts to install the device drivers and restart the computer when prompted.
  2. Once Windows has restarted, connect the USB serial adapter to your computer.
  3. Your computer will automatically complete the driver installation and your device should be ready to use.

Prior to installing this device, ensure that your operating system is up to date (for example, you have installed the most recent service pack).

To install the driver:

  1. Download the latest drivers from the StarTech.com website (http://www.startech.com/Support). You can find the part number and product ID on the product’s packaging.

Note: Windows will typically save the files to the Downloads folder that is associated with your user account (for example, C:\Documents and Settings\your_name\My Documents\Downloads).

  1. Once the download is complete, right-click the zip folder that you downloaded, select Extract All, and follow the on-screen instructions.
  2. In the list of extracted files, double-click the Setup.exe file.
  3. Follow the on-screen prompts to install the device drivers and restart the computer when prompted.
  4. Once Windows has restarted, connect the USB serial adapter to your computer.
  5. Your computer will automatically complete the driver installation and your device should be ready to use.

Troubleshooting

Older applications that use serial communication often use legacy hardware addresses that do not work with PCI, PCIe, or USB to Serial products. We recommend contacting the software provider/support team to check if this is the case.

When you troubleshoot issues with a serial device, there are some quick tests that you can complete to rule out potential problems. You can test to make sure that the following components are working correctly and are not the source of the issue:

  • Serial cables

  • Serial ports

  • Serial devices

To test your setup components, try the following:

  • Use the serial cable, serial port, and serial device in another setup to see if the problem is with the components or the setup.

  • Use a different serial cable, serial port, and serial device in your setup to see if the problem persists. Ideally, you should test a component that you know works in another setup.

When you test your cables, it is recommended that you do the following:

  • Test each cable individually.

  • Use short cables when you are testing.

When you test the serial ports and serial device, it is recommended that you do the following:

  • Press the Windows key + R, type devmgmt.msc, and press Enter to open Device Manager. Check to see if your device is listed under Ports (COM & LPT).

  • Make sure that the COM port number is the correct number for the serial device and that the software being used to connect the computer to the serial device uses the correct COM port number. 

  • If the device is listed with an error, follow the instructions on the website to reinstall the drivers.

Note: Some serial devices work only if the COM port number is between a certain range. For example, COM1 to COM4.

To check whether or not an RS-232 serial port is working, perform an RS-232 loopback test by doing the following:

  1. If your serial port is not female, convert it by taking a female/female cable or gender changer and plugging it into the serial port.
  2. Take a metal paperclip or wire and cross pins 2 and 3. If you look closely at the female end, the pins should be numbered.
  3. Open a telnet session on the COM port number of the device that you are testing. To find out the COM port number, refer to the following FAQ: https://www.startech.com/faq/com-port-listing-windows.

Note: To open a telnet session on the COM port, you need a telnet client like PuTTY or Hyper Terminal. Windows XP comes with Hyper Terminal.

  1. When the session is open, anything you type into it you should see. The loopback test fails when you cannot see what you are typing.

If the loopback test fails, make sure that the serial cable or gender changer that you are using works and that the adapter is in the correct port. 

You can check multiple ports at the same time by opening multiple sessions, putting the loopback adapter on one port, and trying to type into each session.  When you can see what you are typing, you know that the COM port is working and you can see which port number the physical serial port is. Close the window for the port that you just tested to speed up the testing of the remaining serial ports.

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If the USB device does not work after your computer has been in extended hibernation, it is likely that Windows has automatically turned off the USB Root hub to save power. 

The steps below outline how to configure the USB root hub to stay on during hibernation, to prevent this from happening.
 

Windows 10 / 8

  1. On your keyboard, press the Windows key + X and select Control Panel.
  2. Click Hardware and Sound, then click Power Options.
  3. Click Change plan settings for the plan you want to change.
  4. Click Change advanced power settings.
  5. Click the plus sign (+) next to “USB settings” and “USB selective suspend setting” to expand the options and change the setting to Disabled.
  6. Click OK to apply the setting.

Note: You may need to disconnect and re-connect your USB device after applying these settings to re-establish the connection.

Windows 7 / Vista

  1. Click the Start button and select Control Panel.
  2. Click Hardware and Sound, then click Power Options.
  3. Click Change plan settings for the plan you want to change.
  4. Click Change advanced power settings.
  5. Click the plus sign (+) next to “USB settings” and “USB selective suspend setting” to expand the options and change the setting to Disabled.
  6. Click OK to apply the setting.

Note: You may need to disconnect and re-connect your USB device after applying these settings to re-establish the connection.

Windows XP

  1. On your desktop, right-click the My Computer icon and select Properties.
  2. Click the Device Manager tab.
  3. Expand Universal Serial Bus controllers by clicking the arrow to the left of it.
  4. Right-click the first USB Root Hub device and select Properties.
  5. Click the Power Management tab.
  6. Clear the box next to Allow the computer to turn off this device to save power.
  7. Click OK to apply the setting.
  8. Repeat steps 4-7 for any remaining devices in the Universal Serial Bus Controllers section with “Root Hub” in the name.

Note: You may need to disconnect and re-connect your USB device after applying these settings to re-establish the connection.

How To

To confirm that Windows detects your USB device, complete the following:

  1. Press the Windows key+R, type devmgmt.msc, and press Enter.
  2. In Device Manager, under the appropriate heading, confirm that your expansion card is listed and that there isn't an exclamation mark next to it.  For example, a USB controller card would be under Universal Serial Bus controllers.

Your USB device is listed according to the name of the chipset. To determine the name of the chipset of your USB device, navigate to www.StarTech.com and look on the Technical Specifications tab for your product.

To confirm that the Mac OS detects your USB device, complete the following:

  1. Click the Apple icon.
  2. Click About This Mac.
  3. Click More Info or System Report.
  4. Under the appropriate heading, confirm that your USB device is listed and that there isn't an error. For example, a network card would be under Ethernet Cards.

You may need to refresh the System Information page after you plug in your device.  To do so, press Command R with the System Information page open.

Your USB device is listed according to the name of the chipset. To determine the name of the chipset of your USB device, navigate to www.StarTech.com and look on the Technical Specifications tab for your product.

Common Issues

Use a USB to Serial product that features COM Port Retention.  These products will store settings that are unique to the connected device in non-volatile memory, allowing you to retain the desired settings regardless of the USB Port to which the adapter is connected.

Compliance and safety

Compliance letters

  • RoHS
    • Language: English
  • WEEE
    • Language: English

Safety Measures

  • If product has an exposed circuit board, do not touch the product under power.
  • If Class 1 Laser Product. Laser radiation is present when the system is open.
  • Wiring terminations should not be made with the product and/or electric lines under power.
  • Product installation and/or mounting should be completed by a certified professional as per the local safety and building code guidelines.
  • Cables (including power and charging cables) should be placed and routed to avoid creating electric, tripping or safety hazards.
*Product appearance and specifications are subject to change without notice.

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(5 Stars)

Perfect for Network Device Configuration

By: SOHW - 05/31/2017
Bought this way back in 2013 for use with my college computer program which involved a lot of network device configuration (primarily with Cisco switches, routers, and firewalls). Never had an issue with this adapter functioning as intended. It worked reliably and it's really durable considering I've had it knotted in a ball, and stored in a tight coil but it still works. It's almost 4 years later and I have no concerns about this thing lasting me a decade or above. Never did use the parallel portion. If there's any complaint I have, it's that it feels a little cheap since it's just plastic, and it looks very plain with just the grey. Making it like a black matte plastic like the many video adapters, and adding the company logo would be a nice change.
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