How to Configure and setup a Grandstream GRP26XX/GXP Series IP Phone, follow these steps:

1. Connect the GRP phone to your network: Use an Ethernet cable to connect the phone to your local network or router. Make sure the network has DHCP enabled so that the phone can obtain an IP address automatically.
2. Power on the phone: Plug in the power adapter or use Power over Ethernet (PoE) if your network supports it. The phone will boot up and display the Grandstream logo.
3. Obtain the IP address: On the phone’s screen, navigate to the “Menu” or “Settings” option using the arrow keys, and select “Status.” Look for the IP address assigned to the phone. Note it down as you will need it to access the web configuration interface.
4. Access the web configuration interface: Open a web browser on a computer connected to the same network, and enter the IP address of the phone in the browser’s address bar. Press Enter, and you should see the login page for the phone’s web interface.
5. Log in to the web interface: Enter the default username and password to log in. The default username is “admin,” and the random password available on the sticker at the back of the IP- Phone.
6. Configure basic settings: Once logged in, you’ll have access to the phone’s configuration interface. Explore the different sections and configure basic settings such as the time zone, language, and network settings (if needed). Save the changes after making any modifications.
7. Set up unique SIP accounts: To configure unique SIP accounts on your GRP phone, navigate to the “Account” or “SIP Account” section in the web interface. Click on “Add Account” or a similar option to create a new SIP account. Fill in the required information for each account, including the SIP server details, authentication credentials, and other account-specific settings. Make sure to use unique settings for each SIP account, such as unique usernames, passwords, and extensions.
8. Additional configuration: Depending on your requirements, you may need to configure advanced features such as call routing, audio settings, security settings, and more. Refer to the phone’s user manual or the Grandstream website for detailed instructions on these specific configurations.
9. Save and apply changes: After completing the desired configurations, review your settings and click on the “Save” or “Apply” button in the web interface to save and apply the changes to the phone.
10. Test the phone: Once you’ve configured the GRP phone, you can test it by making a call or receiving a call using the configured SIP accounts. Check if the audio quality is satisfactory and verify that all the features you require are functioning correctly.

Remember to consult the user manual provided by Grandstream for your specific phone model, as the steps may vary slightly depending on the phone’s firmware version and features. It’s important to use unique settings for each SIP account to ensure proper functionality and avoid conflicts.