Grandstream UCM6304A Audio Series IP PBXs

The UCM6304A is part of Grandstream’s UCM6300 Audio series—on‑premise IP‑PBX appliances designed for unified business communications. It combines voice, instant messaging, audio conferencing, facility access, and mobility into a single scalable system. It includes the free Wave App for desktop, mobile, and SIP endpoint connectivity

Grandstream UCM6304A Audio Series IP PBXs Specifications

• User & Call Capacity

  • Up to 1,000 users

  • Supports 150 concurrent calls (standard)

  • Supports 120 concurrent SRTP encrypted calls

• Conferencing

  • Up to 7 audio conferencing bridges

  • Maximum of 120 conference participants

• Analog & Telephony Ports

  • 4 FXS ports (for analog phones)

  • 4 FXO ports (for PSTN lines)

  • Lifeline support on FXS/FXO ports

• Network Interfaces

  • 3 Gigabit RJ45 ports (LAN/WAN/Configurable modes)

  • Supports NAT router mode, dual IP mode

  • PoE+ supported on applicable ports

• Peripheral Connectivity

  • 2 × USB 3.0 ports

  • 1 × SD card slot

• Display & Controls

  • 320×240 color LCD screen with touch navigation

  • Multi-function reset button (factory reset/reboot)

• Audio and Fax Codec Support

  • Opus, G.711 μ/a-law, G.722, G.729A/B, G.723.1, iLBC, GSM

  • T.38 Fax, Pass-Through Fax

  • Acoustic echo cancellation, jitter buffer, and packet loss concealment

• VoIP Protocols & Network Support

  • SIP, RTP, SRTP, TLS, TCP/UDP, DHCP, NTP, LDAP, IPv6

  • VPN (OpenVPN, L2TP), 802.1X authentication

  • Layer-2 and Layer-3 QoS

• Security Features

  • Secure boot and unique certificates

  • SRTP, TLS, HTTPS encryption

  • Fail2ban, DoS protection, firewall rules

  • Randomized default passwords

• Call Features & Management

  • Call routing, call queues, IVR (multi-level), ring groups

  • Voicemail, call forwarding, call parking, paging/intercom

  • Recording, fax-to-email, DND, BLF, caller ID

  • ACD with skill/workload-based routing

• Provisioning & Integration

  • Zero-Config auto-provisioning

  • Compatible with Grandstream GDMS cloud platform

  • Full API access for CRM/PMS and third-party integration

  • Supports LDAP directory, push provisioning

• Power Supply

  • Input: 100–240V AC, 50/60Hz

  • Output: 12V DC, up to 2A

• Hardware Form Factor

  • Dimensions: 270 × 175 × 36 mm

  • Weight: approx. 0.75 kg

  • Mountable on desktop or rack

• Operating Environment

  • Operating temperature: 0°C to 45°C

  • Storage temperature: -10°C to 60°C

  • Humidity: 10% to 90% non-condensing

• Certifications & Compliance

  • FCC, CE, RCM, ITU-T K.21

  • Meets international safety and EMC standards