Device Not Found? How to Access a NET232/NET485 with Different Subnets

If you cannot access your NET232 or NET485 device because it is configured with an IP address belonging to a different network segment (a different subnet than your PC), use one of these three options to access the configuration settings.

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Option 1: Temporarily Change Your PC's IP Address (Recommended)

The easiest method is to temporarily change your own computer's IP address so that it belongs to the same subnet range as the NET232/NET485 device.

Key Steps:

1. Identify the Device's Subnet: Check the current IP address of the NET232/NET485. For example, if the device is 192.168.2.150, its subnet is 192.168.2.x.
2. Navigate to IP Settings: Follow the steps below for your OS to reach the **Internet Protocol Version 4 (TCP/IPv4) Properties** window.
3. Change the IP: Select the option to "Use the following IP address" and manually enter an IP address that is in the **same range**, but different from the device's IP.
4. Access and Reconfigure: Access the device's web or Telnet configuration and change its IP address to one that belongs to your **normal subnet** (e.g., 192.168.1.x).
5. Revert Changes: Change your PC's network settings back to their original configuration (e.g., **"Obtain an IP address automatically"**).

Navigation Path for Windows 11:

Settings → **Network & Internet** → **Advanced network settings** → **More network adapter options** → Right-click your adapter → **Properties** → **Internet Protocol Version 4 (TCP/IPv4)** → **Properties**

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Option 2: The "ARP Trick" (Using the MAC Address)

The **ARP Trick** works reliably on **Windows 11**. This method allows you to temporarily assign an accessible IP address to the NET232/NET485 device using its MAC address, without changing your PC's IP.

1. Prerequisite: Enable Telnet Client

For Windows 7, 8, 10, and **Windows 11**, you must enable the Telnet Client feature:

1. Press the **Windows key + R**, type optionalfeatures, and press Enter (or go to **Control Panel** → **Programs** → **Turn Windows features on or off**).
2. Check the box for **Telnet Client** and click **OK**.

2. ARP Trick Steps

1. Get the MAC Address: Find the device's physical MAC address (e.g., 00-20-4A-11-22-33), usually printed on a label.
2. Open Command Prompt (Run as Administrator is recommended).
3. Assign the Temporary IP: Use the arp -s command to bind the MAC address to a temporary IP that is within your subnet.
4. Execute Telnet 1 (Intentional Failure): Attempt to connect to port 1. This connection **will fail**, but it is necessary for the device to accept the temporary IP.
5. Access Configuration: Use Telnet to connect to the configuration port (9999).
6. Enter Setup Mode: Press **Enter** when prompted for Setup Mode.

Command Examples:

  // 1. Assign the Temporary IP:
  arp -s 192.168.1.200 00-20-4A-11-22-33
  
  // 2. Connection attempt (must fail):
  telnet 192.168.1.200 1
  
  // 3. Access Configuration Mode:
  telnet 192.168.1.200 9999
  
  // *** Press ENTER when prompted by the system ***
  

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Option 3: Direct Serial Connection (NET232 ONLY)

If you have a NET232 (this does not work with NET485), you can override the network configuration by connecting it directly to your PC via the serial port (RS-232).

Steps:

1. Physical Connection: Plug the **NET232** directly into your PC's serial port or a USB/RS232 adapter.
2. Power Down: Unplug the power source from the NET232.
3. Open Emulator: Launch a terminal emulation program (like **PuTTY** or **Tera Term**) and configure a **Serial connection** using the correct COM Port.
4. Forced Setup Access:
   • **Hold down the 'x' key** on your keyboard.
   • While holding 'x', **reconnect the power source** to the NET232.
5. Enter Setup Mode: Press **Enter** when the terminal program prompts you (Be quick! The timeout is short).