1 Port RS232 Serial Ethernet Device Server - PoE Power Over Ethernet

Connect to, configure and remotely manage an RS-232 serial device over an IP network

Product ID: NETRS2321POE

1 stars (5 reviews) |
  • Supports standard Ethernet or Power over Ethernet (POE)
  • Supports UDP, IP, TCP, ICMP, HTTP, DHCP and ARP-Ping protocols
  • Wall mountable
Your price
€219,99 EUR excl. VAT
€263,99 EUR incl. VAT

The NETRS2321POE 1 Port RS232 Serial Ethernet Device Server - PoE (Power Over Ethernet) allows you to install your RS232 devices anywhere on your TCP/IP Ethernet WAN/LAN, and access them as if they were right beside you - even over the Internet!

The Serial Device Server is designed to function seamlessly with your other integrated and add-on serial ports as if they were right inside your computer. Perfect for industrial automation, security, Point of Sale, or any long-range serial application, delivering reliable performance in any environment.

The Ethernet/serial device server supports PoE (Power over Ethernet) when connected to a PoE compliant device - eliminating the need for an external power supply and outlet, and making it easier to situate the device server as needed.

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


  • Manufacturing (CNC machinery, process control equipment, bar code scanners, serial printers)
  • Security (UPS control, access key panels, video cameras, card readers)
  • Environmental Control (lighting, temperature, clocks)
  • POS (credit/debit card readers, receipt printers, bar code scanners, cash registers, scales)
  • Hospital (monitoring equipment, nurses' stations)
  • Hotel Front Desk (serial printers, bar code scanners, keyboard, mouse, receipt printer, credit/debit card reader)
  • Hospitality/Restaurant (credit card/debit card reader, serial printers)

The StarTech.com Advantage

  • PoE support gives you the freedom to situate your serial device where it is needed even when no power outlet is available
  • IP-based connection to your serial devices allows remote administration from anywhere; even over the Internet
  • Remotely connect to multiple NETRS2321POE units with a single PC for simple and efficient management of devices from a single location

Partner Numbers

  • Ingram Austria V933059
  • UPC 065030834162



Warranty Information Warranty 2 Years
Connector(s) 1 - Connector Type(s) DB-9 (9 pin, D-Sub)
Environmental Operating Temperature 0°C to 55°C (32°F to 131°F)
Storage Temperature -20°C to 85°C (-4°F to 185°F)
Humidity 5~95% RH
Hardware Industry Standards IEEE 802.3af Power-over-Ethernet
Indicators 3 - LED Indicators Heartbeat, Link/Activity, 10/100 Mbps
Packaging Information Package Height 70 mm [2,8 in]
Package Length 19,2 cm [7,6 in]
Shipping (Package) Weight 963 g [34,0 oz]
Package Width 29,6 cm [11,7 in]
Performance Maximum Data Transfer Rate 115.2Kbps
Data Bits 6, 7, 8
Stop Bits 1, 2
MTBF 233,403 Hours
Supported Protocols UDP, IP, TCP, ICMP, HTTP, DHCP, ARP-Ping
Physical Characteristics Weight of Product 259 g [9,1 oz]
Color Black
Material Aluminum
Product Length 10,7 cm [4,2 in]
Product Width 66,3 mm [2,6 in]
Product Height 2,5 cm [1,0 in]
Power Power Source AC Adapter Included
Input Voltage 100 - 240 AC
Input Current 0.3 A
Output Voltage 12V DC
Output Current 0.1A
Center Tip Polarity Positive
Plug Type M
Power Consumption (In Watts) 1.2
Software OS Compatibility Windows® Vista (32), XP (32), 2000
Special Notes / Requirements Patents and Licenses The following patents are licensed for this product. This list might not be all inclusive.
• United States Patent No. 5,406,260 (expired)
• United States Patent No. 6,650,622
• United States Patent No. 7,457,250
• United States Patent No. 8,155,012
• United States Patent No. 8,902,760
• United States Patent No. 8,942,107
• United States Patent No. 9,019,838
• United States Patent No. 9,049,019
• United States Patent Application No. 14/695,456
• United States Patent Application No. 14/726,940
What's in the Box 1 - Included in Package Industrial Serial over IP Device Server
Universal Power Adapter (NA/UK/EU)
Instruction Manual



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Frequently Asked Questions


Installation for the NETRS2321POE involves software installation, as well as the setup of a virtual serial port using the software.

To install the software, complete the following:

  1. Download the software from www.startech.com/NETRS2321POE#dnlds.
  2. Right-click the folder.
  3. Click Extract all.

Once the software is extracted, it will have to be run to first configure the device. To do this, complete the following:

  1. Connect the NETRS2321POE to your computer or network using an Ethernet cable.
  2. Connect it to a power source.
  3. Open the extracted folder from Step 3.
  4. Open the IP-Search-Utility folder.
  5. Right-click Etm.exe.
  6. Click Run as administrator.

The software should locate the NETRS2321POE. If it is required to change the IP address of the device, perform steps 6-9. If not, proceed to step 10.

  1. Click Config.
  2. Click IP Address.
  3. Enter the preferred IP address.
  4. Click OK.

Note: Ensure that the IP address given matches your network. If the device is connected directly to your PC, disconnect it and then connect it to your network. Ensure that you can still see the device by refreshing the Ethernet Manager.

  1. Click Config.
  2. Click Device Settings to edit the port settings.

Note: By default, there is no password required to log in.

  1. Click Login.
  2. Enter any required port settings, if necessary.

Note: The Socket port of serial I/O number is needed for mapping the COM port to the PC, so this should be noted.

  1. Click Update.

After the device is configured, a different piece of software will need to be run to create the virtual COM port. To do this, complete the following:

  1. Open the Virtual-Com folder from the extracted zip file.
  2. Open the appropriate folder for your operating system.
  3. Right-click VSerPortConsole.exe.
  4. Click Run as administrator.
  5. Right-click in the window.
  6. Click add port.

Note: The default values can be used, or the COM port can be changed if a specific one is needed.

  1. Right-click on the port.
  2. Click add net.
  3. Enter the IP address and socket port of the NETRS2321POE.
  4. Click OK.


In order for the serial device and your computer to communicate to each other, they both need to be on the same physical network and the same subnet.

To connect your serial device and your computer to the same physical network, plug both devices into the same router. 

Typically, in order for devices to be on the same subnet, the first three numbers of the IP address must match. The fourth number of the IP address must be different, as two devices cannot have the same IP address. For example, if your computer’s IP address is, then the subnet is 192.168.0.XXX. You can replace the XXX with any number, as long as it is not currently in use by another device.

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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This device's default static IP address is

  1. Make sure that the NETRS2321POE is on the same network as your computer.
  2. In an Internet browser, enter the IP address of the unit. The default IP address is
  3. In the password field, enter the password. There is no password by default.

Press the Restore Default button on the device. This will immediately restore the unit to its default settings.

You should not upgrade your device's firmware if you do not have any issues with the functionality of your device. The only time you should consider an upgrade is if you are experiencing a problem with the device, and you have confirmed that the firmware addresses this problem.  You can confirm this is the case by reviewing the documentation included with the firmware or by consulting with our Technical Support team. Incorrectly upgrading firmware can result in diminished performance so it is best to contact StarTech.com if you would like to perform this operation.

How To

To troubleshoot this issue, you can try the following:

  • Ping the serial device.
  • Connect the serial device directly to the computer and ping the device.
  • Connect to the web interface (if there is one) or connect using the included software.

Before you begin, make sure that the serial device is on the same network and subnet. For more information, see this FAQ: http://www.startech.com/faq/serial_ip_networks_and_subnets.  If the device starts with an IP address that is not on your subnet, change your IP address to match the subnet being used before you continue.

Ping the serial device

If the serial device and your computer are on the same network and subnet, try pinging the device. 

To ping the device using a computer that is running a version of Windows XP, do the following:

  1. Click Start.
  2. Click Run.
  3. Type ping <IP address> and press Enter. For example, ping

To ping the device using a computer that is running a version of Windows Vista or Windows 7, do the following:

  1. Click Start.
  2. Click Accessories.
  3. Click Command Prompt.
  4. Type ping <IP address> and press Enter. For example, ping

To ping the device using a computer that is running a version of Windows 8, do the following:

  1. Press the Windows key + X.
  2. Click Run.
  3. Type cmd and press Enter.
  4. Type ping <IP address> and press Enter. For example, ping

To ping the device using a computer that is running a version of Mac OS, do the following:

  1. Double-click the hard drive.
  2. Double-click Applications > Utilities > Network Utility.
  3. Click the Ping tab.
  4. Enter the IP address in the Please enter the network address to ping field.
  5. Enter the number of packets that you want to test with.

If you receive replies from the IP address, then you can see the device on the network and the issue is with something else.

Connect the serial device directly to the computer

To connect the serial device directly to the computer that you are troubleshooting with, complete the following:

  1. Use a crossover Ethernet cable to connect the device and the computer.
  2. Try pinging the device again.
  3. If you cannot ping the device, use a different computer, Ethernet cable, and serial device (if one is available).

Note: The second computer will need to be on the same network and subnet as the serial over IP device.

  1. If you still cannot ping the device, contact support.

Make sure that you are working in a secure environment

  1. Unplug the connection between your modem and your router. 
  2. Disable any firewalls (especially Windows Firewall), antivirus programs, and security programs that are currently running. 
  3. Try accessing the web interface (if the device has one) or try to connect using the included software.

If you still cannot connect to the device's web interface or by using the included software, contact support.

If you can access the web interface or connect using the included software, one at a time turn on your firewalls, antivirus programs, and security programs. Each time that you turn on software and cannot connect to the web interface or by using the included software, add an exception for the serial device to what you last re-enabled.

Before You Buy

Virtual COM port

One of the most common applications of a network serial device is to use it to make a standard serial device accessible on a network. To do this, you need to connect a standard serial device to the DB-9 port on the network serial device. Next you need to connect the network serial device to a TCP/IP network using an Ethernet connection, and then install software on a client machine in order to access the network serial device. The software on the client machine communicates with the network serial device and creates (maps) a virtual COM port on your computer system. The virtual COM port is identical to a physical COM port and can be used in the same way.

Serial IP extender

You can use two network serial devices to extend a serial connection over a TCP/IP network. To do this, you need to configure one serial device as a client and the other as a server. The client and server are configured to transmit and receive data to their respective IP addresses and TCP ports. The serial settings must match for all connected serial devices, including the UART on both units. Depending on the serial device that you are using, you can use the provided software or the web interface to set the configurations.

UDP to serial adapter

You can use a network serial device to translate UDP data to a standard serial connection. The serial device is configured to listen for UDP traffic from specific IP addresses and ports, and will asynchronously transmit the data out of the serial port on the device. To do this, you need to configure UART on the network serial device to match the specifications of the serial receiver.

Compliance and safety

Compliance letters

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.

Customer Reviews

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1 - 5 of 5 Reviews
(1 Stars)

Doesn't work with today's operating systems.

By: Chris from Pensacola - 07/08/2016
Can't use with Windows 7 or 10. Only works with older, unsupported operating systems.
| Helpful?
Barry, Customer Support on 19/07/2016 05:48:58
Hello Chris, Thanks for reaching out. You are correct. This device only supports Windows 2000, XP & Vista. Due to the age of this device, updating to support Windows 7 through Windows 10 was not possible. We do however offer a newer model, the NETRS2321P. This model offers OS support from Windows 2000 through Windows 10, as well as Server OS support, 2003 through 2012 R2. It however, does not support POE. If POE is a requirement in your setup, have a look at our POE injectors such as the POEINJ1G. Should you need anything else, please reach out to our technical advisors at http://www.startech.com/support. Thank you,
(1 Stars)

Device not seen by Startech DS-Tool software

By: Stephen - 07/27/2017
We use a StarTech NETRS42348PD device with their DS-Tool software (V1.2) and expected that this device would be seen by that software. It is not, and as such is of no use to us because we run Windows 7 or higher. This oversite should be corrected by StarTech.
| Helpful?
Brian, Customer Support on 04/08/2017 11:22:11
Hi, Thanks for your feedback and review. If you used the DS-Tool software and it was not successful in finding the unit. Please try the following - Directly connect the product with a network cable to a computer - Assign that computer a static IP address on the same subnet (Ex - Open the DS-Tool software and configure the unit or access the web interface using We hope this helps. If it does not, or you have any concerns, please reach out to our Technical Advisors by clicking "Support" at the top of our website. Thank you.
(1 Stars)

Does not support win7/10

By: Stealthsingh - 10/20/2017
Just bought it, needed a poe rs232. This fit the bill, made the wrong assumption that it would be supported on newer OS Needless to say, I am not happy at my laziness.
| Helpful?
(1 Stars)

Very Disappointed

By: FrankB - 09/11/2020
I bought this device because the locations I'll be using in have a POE port but not a power receptacle. There's no excuse for why other very similar devices are supported by Windows 10, but not this device. I had to buy 3rd party software to use this device in my application. Once I found software that can work with this device, it does exactly what I needed it to do.
| Helpful?
(1 Stars)

Nothing in setup changes the arguments for serial.

By: acadiel - 09/22/2020
I have this setup to a US Robotics modem, and use Putty to telnet to port 100 of the serial server. The Web-UI has the baud rate locked at 115200-8N1. However, the modem keeps reporting the speed being locked at 9600, no matter what baud rate I put in the WebUI. I mean, I can deal with 9600, but still, I'd expect the WebUI to change the argument if it's an option.
| Helpful?
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