VoIP telephone adapter Grandstream Networks HT881

The Grandstream Networks HT881 VoIP telephone adapter is an FXO/FXS gateway designed to connect traditional PSTN lines and analog phones to IP networks. It supports multiple voice codecs (G.711, G.723.1, G.726, G.729A, G.729B), T.38 fax, and offers LED indicators for LAN, Power, and WAN. Security features include AES encryption and secure protocols such as HTTPS, SIPS, and SSL/TLS. Its compact dimensions (100 mm × 28 mm × 190 mm) make the HT881 suitable for small offices and distributed deployments.

Advantages

The HT881 provides seamless integration between analog telephony and IP PBX or hosted VoIP services, combining FXO and FXS functionality in a single compact unit. It supports a wide range of codecs for voice quality optimization, T.38 for reliable fax transmission, and multiple security protocols to protect signaling and media. Easy automated provisioning and clear LED status indicators simplify installation and ongoing management.

Suitable for

• Small offices and home offices requiring PSTN-to-VoIP connectivity
• Branch locations that need integration with central IP PBX systems
• Environments requiring reliable fax over IP (T.38)
• Deployments where compact footprint and clear status indicators are needed

Key specifications

• Model: Grandstream HT881
• Ports: FXO and FXS (integrated gateway functionality)
• Supported codecs: G.711, G.723.1, G.726, G.729A, G.729B
• Fax: T.38 support
• Security: AES, HTTPS, SIPS, SSL/TLS
• LED indicators: LAN, Power, WAN
• Dimensions: 100 mm (W) × 28 mm (D) × 190 mm (H)

How to use

Connect the HT881 to your network via the WAN/LAN port and attach analog phones or a PSTN line to the FXS/FXO ports as required. Access the web-based management interface to configure SIP account settings, codec priorities, fax settings (T.38), and security options. Use automated provisioning if available from your provider to simplify bulk configuration; otherwise, complete manual setup through the device GUI. Monitor LED indicators to verify power, network, and WAN status during and after installation.

Recommendations

For best voice quality, prioritize G.711 where bandwidth allows and enable G.729 only when bandwidth is constrained. Enable TLS/SRTP or HTTPS where supported to secure signaling and media. If fax is required, configure T.38 and test end-to-end fax transmission. Use automated provisioning for multiple devices to reduce configuration errors.