Grandstream HT503 is an analog telephone adapter (ATA) featuring 1 analog telephone FXS port and 1 PSTN line FXO port in order to offer backup lifeline support using a PSTN line. The integration of an FXO and FXS port enables remote call origination and termination to and from the PSTN line, known as hop-on and hopoff calling. The 1 FXS port allows for extension of a VoIP service to 1 analog phone. Furthermore, complies with SIP 2.0 standard, supports Universal Plug-in-Play (UPnP), up to 2 SIP account profiles and advanced telephony features.

Key Features:

• 2 SIP account profiles
• 1 FXS port
• 1 FXO port
• 2 10/100Mbps Ethernet ports with integrated NAT router
• T.38 Fax support for creating Fax-over-IP
• 3-way voice conferencing
• Failover SIP server automatically switches to secondary server if main server loses connection
• Supports a wide range of caller ID formats
• Supports advanced telephony features, including call transfer, call forward, call-waiting, do not disturb, message waiting indication, multilanguage promtps, flexible dial plan and more
• Automated provisioning options including TR-069 and XML config files 
• 2 Year Warranty