Introduction
This manual provides comprehensive instructions for the installation, operation, and maintenance of the Grandstream GXP1628 IP Phone. The GXP1628 is designed for small to medium business users, offering advanced VoIP features, high-definition audio, and integrated Power over Ethernet (PoE).
Please read this manual thoroughly before using the device to ensure proper setup and optimal performance.
Package Contents
Verify all items are present in your package:
- GXP1628 phone
- Handset with cord
- Base stand
- Universal power supply
- Network cable
- Quick Installation Guide
- Brochure
- GPL License
Product Overview
The Grandstream GXP1628 is a robust IP phone featuring a 2.9-inch LCD display and dual-port Gigabit Ethernet with integrated PoE. It supports up to 2 lines and 2 SIP accounts, making it suitable for various business communication needs.

Figure 1: Front view of the Grandstream GXP1628 IP Phone, showing the handset, keypad, display, and line keys.
Key Features:
- 2 Dual-Color Line Keys: Supports 2 SIP accounts and up to 2 call appearances.
- 3 XML Programmable Soft Keys: Customizable for various functions.
- 8 BLF Keys: Monitor presence and status of other extensions and facilitate call transfers.
- 3-Way Conference: For enhanced productivity.
- Dual-Switched Gigabit Network Ports: Maximizes connection speeds and call quality, with integrated PoE.
- HD Wideband Audio: Ensures crystal-clear calls.
- Full-Duplex Hands-Free Speakerphone: With advanced acoustic echo cancellation.
- Electronic Hook Switch (EHS): Supports Plantronics headsets.
- 132 x 48 Pixel Backlit Graphical LCD Display: Provides clear call information and menu navigation.
- Multi-Language Support: For diverse user bases.
- Personalized Music Ring Tone/Ring Back Tone: Customization options.
Setup and Installation
Connecting the Phone:
- Connect the Handset: Plug the coiled cord into the handset port on the phone base and into the handset.
- Connect the Base Stand: Attach the base stand to the bottom of the phone.
- Connect to Network (PoE): If using Power over Ethernet (PoE), connect one end of the Ethernet cable to the LAN port on the phone and the other end to a PoE-enabled switch or injector. The phone will power on automatically.
- Connect to Network (Non-PoE) and Power: If PoE is not available, connect one end of the Ethernet cable to the LAN port on the phone and the other end to a network switch/router. Then, connect the universal power supply to the power port on the phone and plug it into a power outlet.
- Connect to PC (Optional): If you wish to connect a PC through the phone, connect an Ethernet cable from the PC port on the phone to your computer's network port.

Figure 2: Rear view of the Grandstream GXP1628 IP Phone, illustrating the various connection ports for network, power, and PC.
Initial Configuration:
Upon first boot, the phone will attempt to obtain an IP address via DHCP. For advanced configuration, such as SIP account setup, refer to the Administrator Guide or contact your VoIP service provider.
Operating Instructions
Making a Call:
- Pick up the handset, press the Speaker button, or press an available LINE key.
- Dial the desired number.
- Press the SEND button or wait a few seconds for automatic dialing.
Answering a Call:
- Pick up the handset.
- Press the Speaker button.
- Press the corresponding flashing LINE key.
Call Features:
- Hold: Press the HOLD button during an active call. Press the flashing LINE key to resume.
- Transfer: During an active call, press the TRANSFER button, dial the target number, and press SEND or the TRANSFER button again (for attended transfer) or hang up (for blind transfer).
- Conference: During an active call, press the CONFERENCE button. Dial the second party's number and press SEND. Once the second party answers, press the CONFERENCE button again to establish the 3-way conference.
- Mute: Press the MUTE button to mute/unmute the microphone during a call.
Maintenance
- Cleaning: Use a soft, dry cloth to clean the phone's surface. Avoid using abrasive cleaners or solvents.
- Environment: Keep the phone in a dry environment, away from direct sunlight, excessive heat, or moisture.
- Firmware Updates: Regularly check for and apply firmware updates to ensure optimal performance and security. Consult your system administrator or Grandstream's official website for update procedures.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Phone does not power on. | No power connection or faulty power supply/PoE. | Ensure power adapter is securely plugged in or PoE switch is active and connected correctly. Test with a known good power source if possible. |
| No dial tone. | Network connectivity issue or SIP registration failure. | Check network cable connection. Verify IP address on the phone's display. Contact your VoIP service provider or administrator to confirm SIP account registration status. |
| One-way audio during calls. | Network Address Translation (NAT) issues or firewall blocking audio ports. | Consult your network administrator to check NAT settings and firewall configurations. Ensure necessary VoIP ports are open. |
| Poor call quality (echo, static). | Network congestion, faulty cable, or environmental interference. | Check network bandwidth. Replace Ethernet cable. Ensure phone is not near strong electromagnetic interference sources. |
Specifications
| Feature | Detail |
|---|---|
| Product Dimensions | 8.7 x 7.6 x 2.99 inches |
| Item Weight | 1.76 pounds (0.8 Kilograms) |
| Model Number | GXP1628 |
| Display | 132 x 48 pixel backlit graphical LCD |
| SIP Accounts | 2 |
| Line Keys | 2 dual-color line keys |
| Network Interfaces | Dual-switched Gigabit Ethernet ports with integrated PoE |
| Audio Features | HD wideband audio, full-duplex hands-free speakerphone with advanced acoustic echo cancellation |
| Headset Support | Electronic Hook Switch (EHS) with Plantronics headsets |
| Power Source | Corded Electric (Universal power supply included) |
| Material | Plastic |
| Color | Charcoal |
| Date First Available | June 2, 2015 |
Warranty and Support
For warranty information, technical support, and additional resources, please visit the official Grandstream website or contact your authorized reseller. Keep your purchase receipt for warranty claims.
Online resources may include FAQs, firmware downloads, and detailed administration guides.