Grandstream HT813 Hybrid ATA — Connect Analog Phones to VoIP with PSTN Lifeline Backup

The Grandstream HT813 is a versatile hybrid analog telephone adapter (ATA) with both FXS and FXO ports, allowing you to bridge analog phone systems to your VoIP network while retaining PSTN lifeline backup. Ideal for businesses, home offices, and service providers upgrading to IP communications without abandoning existing analog infrastructure. Backed by Reef Telecom's industry-leading 10-year warranty and free shipping on orders over $300.

Key Features

• 1 FXS port and 1 FXO port supporting 2 SIP profiles
• PSTN lifeline support — FXS port hard-relays to FXO port during power outages
• Dual 100Mbps Ethernet ports (LAN and WAN) with integrated NAT router
• T.38 Fax-over-IP for reliable fax transmission
• 3-way voice conferencing per port
• Strong AES encryption with per-unit security certificate
• Failover SIP server for automatic switchover if primary server disconnects
• TR-069 automated and secure remote provisioning
• HD voice quality with support for G.711, G.729A/B, G.723.1, G.726, iLBC, and OPUS codecs
• Ultra-compact form factor

Compatibility & Use Cases

The HT813 is perfect for small businesses, home offices, and service providers looking to convert analog phones, fax machines, or alarm systems to VoIP. Its FXO port enables PSTN pass-through and emergency call routing, making it a reliable choice for environments where uptime is critical. Compatible with major SIP platforms and IP PBX systems including Grandstream UCM, Asterisk, FreePBX, and hosted VoIP services.

Free ground shipping on orders over $300. Same-day shipping on orders placed before 4PM EST.

All products include our industry-leading 10 Year Warranty backed by Reef Telecom.