Grandstream UCM6304 IP PBX 4 FXO 4 FXS

UCM6300 4 FXO / 4 FXS

The Grandstream UCM6304 is an on-premises IP PBX in the UCM6300 series with four FXO analog trunks and four FXS analog stations. It registers SIP extensions and SIP trunks while keeping PSTN fallback on copper. Wave, IM, video meetings, and call features run on the appliance without a separate cloud PBX. Typical UCM6304 capacity is in the thousands of users at the software limit, with concurrent call ratings published by Grandstream for this SKU. Use it as the voice core for offices that still need analog lines plus IP phones.

Additionally, FXO ports seize telco analog trunks where SIP is not yet available. Therefore mixed analog/SIP cutovers are straightforward. However, analog trunk quality depends on the telco loop. Consequently, prefer SIP trunks for capacity and keep FXO for failover. FXS ports drive analog handsets, fax, or door phones that cannot move to SIP immediately.

Key Features

• 4 FXO + 4 FXS
  Analog trunks and analog stations on the same chassis as SIP.

• SIP trunks and extensions

  • Standard SIP endpoints (Grandstream and third-party).
  • ITSP SIP trunks with failover to FXO.

• Built-in UC applications
  Auto attendant, ring groups, queues, voicemail, and Grandstream Wave softphone support.

• Security and NAT
  TLS/SRTP options, fail2ban-style protections, and remote extension support when WAN is locked down.

• HA option
  UCM6300 series supports high-availability pairing on supported firmware.

Specifications

What’s in the Box

• UCM6304 appliance

• Power adapter

• Ethernet cable

• Documentation

Why Choose This IP PBX

• Four analog trunks keep PSTN alive during SIP outages.

• Four FXS ports retire analog devices on a schedule.

• On-premises control of recordings and call routing.

• Wave clients reduce desk-phone count for hybrid staff.

Additionally, lock the WAN GUI and use a VPN for remote admins. Therefore do not expose SIP 5060 to the whole internet. However, analog fax still prefers T.38 or a dedicated FXS with correct gain. Consequently, test fax before decommissioning the old analog PBX. Take a backup after the first stable dial-plan.

See networking voice hardware.