If you are choosing a Grandstream PBX for an office, hotel or hospital in Saudi Arabia, the right UCM6300 model is rarely decided by headcount alone. What usually settles it is how many analog landlines you will keep, how many calls run at the same time in the busiest hour, and whether those calls will be encrypted. The series has four models: UCM6301, UCM6302, UCM6304 and UCM6308.
This guide compares the four models using Grandstream’s official datasheet figures, shows how to size extensions and lines, and explains how to pair the PBX with Grandstream IP phones and switches. AZEIDK supplies, installs and programs this equipment as part of its network and communication systems scope.
Key takeaways
- The Grandstream UCM6300 series starts at 500 users and 75 concurrent calls (UCM6301) and goes up to 3,000 users and 450 calls (UCM6308), per the datasheet.
- Each model has 1, 2, 4 or 8 FXO ports for landlines and the same number of FXS ports for analog phones. In most offices this port count decides the model, not the user count.
- The datasheet lists no E1 port for the series, so external lines connect through SIP trunks or FXO ports.
- Encrypted calls (SRTP) reduce capacity: on the UCM6308, from 450 to 300 concurrent calls.
- The Grandstream phones AZEIDK supplies (GRP2614, GRP2670, GXV3470) auto-provision on the PBX through Zero Config and need a suitable PoE switch.
In this article
- What is the Grandstream UCM6300 PBX series?
- Grandstream UCM model comparison: UCM6301, UCM6302, UCM6304 and UCM6308
- How many extensions and lines do you need?
- Can a Grandstream PBX connect to an stc line?
- Pairing the PBX with Grandstream IP phones: which phone for which desk?
- Network and switches: what the PBX needs before installation
- Remote work and branches: Wave and UCM RemoteConnect
- Common mistakes when choosing a Grandstream PBX
- Frequently asked questions
- Conclusion
What is the Grandstream UCM6300 PBX series?
The UCM6300 is an on-premise IP PBX series. Grandstream states it runs on the open-source Asterisk 16 telephony platform and combines voice calls, video calls, video meetings, auto attendant and call center functions in one appliance.
According to the datasheet, all four models share these points:
- Three Gigabit network ports, with the unit working in switch or router (NAT) mode.
- An auto attendant (IVR) up to 64 levels deep, with customizable voice prompts in several languages including Arabic. The web management interface language list in the datasheet does not include Arabic.
- Call queues and automatic call distribution (ACD) based on agent skills and availability, useful for reception and customer service desks.
- Hot Standby support for high availability, and an API for integration with CRM platforms and hotel property management systems (PMS).
- FXS and FXO ports with lifeline capability during a power outage.
The models differ in capacity, analog port count and mounting. See the full listing on AZEIDK’s Grandstream products page.
Grandstream UCM model comparison: UCM6301, UCM6302, UCM6304 and UCM6308
The figures below come from the official series datasheet (version 5.2026). Maximum capacity is rated with the G.711 codec; real capacity also depends on call recording, meetings, codecs and network settings.
| Item | UCM6301 | UCM6302 | UCM6304 | UCM6308 |
|---|---|---|---|---|
| Users (extensions) | 500 | 1,000 | 2,000 | 3,000 |
| Concurrent calls, G.711 | 75 | 150 | 300 | 450 |
| Concurrent SRTP (encrypted) calls | 50 | 100 | 200 | 300 |
| FXO ports (landlines) | 1 | 2 | 4 | 8 |
| FXS ports (analog phones) | 1 | 2 | 4 | 8 |
| Simultaneous public meeting rooms / max participants | 4 / 75 | 8 / 150 | 15 / 200 | 25 / 300 |
| Mounting | Wall or desktop | Wall or desktop | Rack or desktop | Rack or desktop |
| Unit weight | 715 g | 725 g | 2,490 g | 2,550 g |
The datasheet lists rack or desktop mounting for the UCM6304 and UCM6308, and wall or desktop mounting for the UCM6301 and UCM6302. If the network room already has a rack, that is one more factor in the choice.
How many extensions and lines do you need?
Collect four numbers before picking a model, and start with the one that is hardest to expand later:
- Landlines you will keep: each analog line needs an FXO port. A site with four landlines needs at least a UCM6304, even with only 40 staff. The datasheet notes that ports can be expanded by peering with an external FXO gateway.
- Analog devices: fax machines, lift phones and gate phones need FXS ports or an analog telephone adapter.
- Peak concurrent calls: count internal and external calls together in the busiest hour, plus recorded calls and meeting sessions.
- Extensions after growth: current staff, expected growth, and non-personal extensions such as meeting rooms, reception and mobile app users.
In practice the user ceiling is high (500 on the smallest model), so it is rarely the limit in an office. The real limit is usually the FXO port count, followed by concurrent calls for call centers and hotels.
| Scenario | Deciding number | Closest model |
|---|---|---|
| Office or clinic with one landline, everything else on SIP | One FXO port | UCM6301 |
| Company with two landlines, a fax and a gate phone | Two FXO and two FXS ports | UCM6302 |
| Head office with four landlines and an existing rack | Four FXO ports | UCM6304 |
| Hospital or complex with heavy, encrypted call traffic | Concurrent encrypted calls | UCM6308 |
For brand-neutral PBX selection steps, see our guide to IP PBX for business.
Can a Grandstream PBX connect to an stc line?
Yes, in two ways depending on the line type. An analog landline goes into an FXO port. SIP trunks arrive over the network with no analog ports, and the number of trunk channels sets how many external calls can run at once.
stc lists SIP Trunking among its business services and publishes a configuration manual on its website for connecting a customer PBX. The manual specifies G.711 (A-law first) over UDP port 5060, and states that the stc server sends OPTIONS messages to the customer gateway, which the PBX must answer with 200 OK. Because G.711 is the codec behind the UCM6300 capacity ratings, the table above is the realistic reference for stc trunks. Contract details and channel counts are confirmed with the provider.
One point many buyers miss: if the site runs on a digital E1 circuit, the UCM6300 datasheet lists no E1 port. The options are to move to SIP with the provider or to choose a PBX that accepts E1 directly, such as the Yeastar models covered in our article on IP PBX brands in Saudi Arabia.
Pairing the PBX with Grandstream IP phones: which phone for which desk?
The UCM6300 auto-discovers and auto-provisions Grandstream endpoints through Zero Config, so each phone registers and pulls its settings without manual programming. These are the devices AZEIDK supplies, with figures from each official datasheet:
| Device | Datasheet highlights | Best for |
|---|---|---|
| GRP2614 phone | 4 line keys, up to 12 SIP accounts, dual screens, Wi-Fi 6 and Bluetooth, dual Gigabit ports, PoE with 4 W max consumption | Staff desks |
| GRP2670 phone | 12 lines and 16 SIP accounts, 7-inch touch screen, 5-way audio conference, supports an extension module | Reception and secretaries |
| GXV3470 video phone | Android 14, 2 MP camera, 16 SIP accounts, 3-way 720p video conference, PoE/PoE+ | Managers and small meeting rooms |
| HT802 v2 analog adapter | Two FXS ports, T.38 fax support | Fax machines and legacy analog phones |
| GDS3710 door station | 1080p video, RFID card reader, two relays for an electric lock, PoE | Office and building entrances |
| GSC3506 v2 paging speaker | 30 W speaker, SIP and multicast paging, PoE/PoE+/PoE++ | Paging in warehouses and corridors |
With one brand for the PBX, door station and paging speaker, staff answer visitors and page the building from their desk phone. Any standard SIP phone from another brand will also work, but the datasheet describes Zero Config provisioning for Grandstream endpoints.
Network and switches: what the PBX needs before installation
Phones draw power from the switch over PoE, so work out the power budget before ordering. The Grandstream GWN7800 switches AZEIDK supplies come in PoE versions, GWN7801P, GWN7802P and GWN7803P, with total PoE budgets of 130, 240 and 370 W respectively and up to 30 W per port, per the datasheet.
Worked example: 20 GRP2614 phones at a maximum of 4 W each need about 80 W, well within a GWN7802P. Leave headroom for cameras or access points on the same switch.
Put voice on its own VLAN with QoS priority; the PBX and phones support 802.1Q, 802.1p and DiffServ per their datasheets. Put the PBX and switch on a UPS, or every phone goes dark at the first power cut.
Remote work and branches: Wave and UCM RemoteConnect
The free Wave app runs on Windows, macOS, web browsers, Android and iOS, letting staff call from their extension and join UCM meetings from outside the office. Grandstream’s UCM RemoteConnect is a cloud NAT traversal service for secure remote connections, and GDMS provides cloud setup, management and monitoring of the devices.
The result is on-premise control with remote access similar to a cloud PBX. Choosing between the two still depends on the number of branches, internet quality and the organization’s policy on where call data is stored.
Common mistakes when choosing a Grandstream PBX
- Sizing by headcount only, then finding there are not enough FXO ports for the landlines.
- Assuming the UCM6300 has an E1 port for a site on a digital circuit.
- Sizing with the standard call figure while enabling SRTP encryption, which lowers real capacity.
- Buying a switch without PoE or with a power budget too small for all phones.
- Forgetting analog devices (fax, lift, gate) until commissioning day.
- Running the PBX without backup power or without a separate voice VLAN.
- Importing devices without checking conformity requirements. See our article on the SABER certificate of conformity for network and telecom devices.
Frequently asked questions
How much does a Grandstream PBX cost?
The price depends on the model, the number of phones and switches, installation and programming. For the cost drivers and how to compare quotes, read IP PBX price in Saudi Arabia.
What is the difference between the UCM6302 and UCM6304?
The UCM6304 has twice the analog ports (4 FXO and 4 FXS versus 2 and 2) and twice the concurrent calls (300 versus 150), and it mounts in a rack. The UCM6302 is a compact wall or desktop unit.
Can the PBX connect to an stc line?
Yes. A landline connects through an FXO port and SIP trunks connect over the network. The configuration manual on stc’s website specifies G.711 over UDP 5060.
Does the Grandstream PBX support Arabic?
The auto attendant supports Arabic voice prompts per the datasheet. Arabic does not appear in the web interface language list.
Do phones from other brands work with a Grandstream PBX?
Yes, any standard SIP phone can register. Zero Config auto-provisioning is described in the datasheet for Grandstream endpoints; other phones are set up manually or with configuration files.
Is the Grandstream UCM a cloud PBX?
The appliance sits on your premises, but UCM RemoteConnect and the Wave app allow calling from outside the office, and GDMS allows cloud management.
Conclusion
Choosing a Grandstream PBX starts with the lines, not the staff: how many landlines you keep, whether you have an E1 circuit, how many calls run at peak and whether they are encrypted. Then pick phones by the role of each desk, and finish with a PoE switch that has enough budget and a separate voice network. In that order, you avoid buying a model bigger than you need or smaller than your lines.
Need a UCM model recommendation for your site? Send us your extension count, current line types and analog devices, and we will propose the PBX, phones and switch with their datasheets. Talk to the AZEIDK team
