Description
The Grandstream UCM6308 is the flagship model in the UCM6300 Series, built for organizations that need serious scale and rich collaboration in one appliance. It combines 8 FXS ports for analog phones and faxes with 8 FXO ports for PSTN connectivity, while delivering up to 3,000 users and 450 concurrent calls. What sets it apart is the integrated video conferencing platform supporting up to 25 simultaneous rooms, 300 total participants, and multiple video feeds — all accessible through the free Wave app, desktop, or SIP endpoints. Powered by a stronger 6-core processor and 4GB RAM, it handles demanding hybrid environments with advanced voice and video codecs, robust security, and flexible management options.
The Telecom Spot Take
For our customers running larger offices or multi-site operations that want both high-capacity voice and meaningful video collaboration without relying entirely on cloud services, the UCM6308 stands out as the strongest choice in the series. The jump to 3,000 users and 450 concurrent calls gives substantial headroom for growth, while the video capabilities (up to 300 participants and 9 video feeds) support real internal meetings and hybrid teams. The full 8+8 analog port density is excellent for organizations that still need legacy phones, faxes, or PSTN failover. The more powerful hardware and full video codec support make this the model to choose when video quality and participant scale matter alongside traditional telephony features.
Key Features
- 8 FXS + 8 FXO ports with lifeline capability — Directly connect analog phones, fax machines, and PSTN lines while maintaining critical communications during power events.
- Up to 3,000 users and 450 concurrent calls — Enterprise-level capacity with significant headroom for growing organizations and busy periods.
- Built-in video conferencing with up to 300 participants — Host up to 25 simultaneous video rooms with support for up to 9 video feeds. Join via Wave app, desktop, or SIP video endpoints.
- Full video codecs (H.265, H.264, H.263, H.263+, VP8) + Full-band Opus voice — High-quality video and clear audio even on variable networks with up to 50% packet loss resilience.
- Free Wave app with video & collaboration tools — Desktop, web, and mobile access for calls, instant messaging, file sharing, and video meetings from anywhere.
- Zero-configuration provisioning and GDMS cloud management — Endpoints self-configure and IT teams centrally manage everything through a secure cloud dashboard.
- High Availability and UCM RemoteConnect — Hot-standby redundancy for maximum uptime plus secure remote access for distributed teams.
- Powerful hardware and comprehensive features — 6-core processor with 4GB RAM and 128GB storage handles demanding workloads plus full API integrations and enterprise security.
Technical Specifications
Capacity
- Users: 3,000
- Concurrent calls (G.711): 450
- Max concurrent SRTP calls: 300
- Video conference rooms: Up to 25 simultaneous
- Max video participants: 300 total (up to 9 video feeds)
Analog & PSTN Ports
- 8 FXS RJ11 ports (lifeline capable)
- 8 FXO RJ11 ports (lifeline capable)
Network & Hardware
- 3× self-adaptive Gigabit RJ45 ports (switched/routed/dual mode) with PoE+
- 2× USB 3.0 ports + 1× SD card slot
- 6-core processor, 4GB RAM + 128GB storage
- Rack-mount and desktop installation
Voice & Video Codecs
- Voice: Full-band Opus, G.711, G.722, G.722.1, G.723.1, G.726, G.729A/B, iLBC, GSM; T.38 fax
- Video: H.265, H.264, H.263, H.263+, VP8
- Advanced voice processing with up to 50% packet loss resilience
Management & Security
- ZeroConfig provisioning for Grandstream endpoints
- Full API for CRM/PMS and third-party integrations
- GDMS cloud management and monitoring
- Secure boot, unique certificate, SRTP, TLS, HTTPS, SSH, 802.1X
- UCM RemoteConnect and High Availability (hot standby) support
Comparison at a Glance
| Feature | UCM6308 | UCM6304 | UCM6308A (Audio) |
|---|---|---|---|
| FXS + FXO Ports | 8 + 8 | 4 + 4 | 8 + 8 |
| Max Users | 3,000 | 2,000 | 1,500 |
| Concurrent Calls (G.711) | 450 | 300 | 200 |
| Video Conferencing | Yes (300 participants, 25 rooms) | Yes (scaled) | No (audio only) |
| Best For | Larger enterprises needing full video + maximum hybrid capacity | Growing organizations with moderate video needs | Voice + analog focused environments |
Frequently Asked Questions
What is the main difference between the UCM6308 and the UCM6308A?
The UCM6308 is part of the full UCM6300 Series with complete video conferencing support (up to 300 participants and multiple video feeds). The UCM6308A is the Audio Series version focused on voice and web meetings with lower overall capacity.
How many people can join video meetings?
Up to 300 participants total across up to 25 simultaneous video conference rooms, with support for up to 9 video feeds.
Can I still use my existing analog phones and fax machines?
Yes. The 8 FXS ports let you connect analog devices directly, and all ports include lifeline capability for continued operation during power outages.
Is the UCM6308 suitable for multi-site or remote teams?
Yes. UCM RemoteConnect provides secure NAT traversal, the free Wave app works on desktop, web, and mobile, and High Availability support helps maintain uptime across locations.
How does video quality compare to cloud platforms?
The UCM6308 uses modern codecs including H.265 and VP8 with optimized real-time handling. Many organizations find the on-premises solution delivers more consistent quality and better control over data and security.
Can I integrate this with my CRM or other business tools?
Yes. A full API is available for third-party integrations including popular CRM and PMS platforms.