The Grandstream UCM6304 IP PBX is a powerful unified communication solution featuring 4 FXO and 4 FXS ports, supporting up to 2000 users and 300 concurrent calls. With Gigabit Ethernet, PoE+, built-in conferencing, and GDMS cloud management, it is ideal for medium-sized businesses integrating VoIP, PSTN, and analog communication systems.