The Grandstream HT841 FXO Gateway is a hybrid VoIP solution featuring 4 FXO ports and 1 FXS port, designed to connect PSTN lines and analog devices to SIP-based networks. With dual Gigabit Ethernet, built-in NAT router, SIP failover, and T.38 fax support, it is ideal for businesses transitioning from traditional telephony to modern VoIP systems.