An IP PBX is a business phone system that handles extensions and outside lines over the data network instead of separate telephone cabling. To choose one, define the number of users, the peak number of concurrent calls, the type of outside lines (SIP trunk, analogue or E1), the IP phones you need, and features such as auto attendant and call recording.
This guide walks through specifying an IP PBX before you ask for quotes, what it needs from the network, and what to put in the request. AZEIDK supplies, installs and programmes IP telephony as part of its network and communication systems in Saudi Arabia.
Key takeaways
- Users (extensions) and concurrent calls are two different capacities, and both size the PBX.
- Outside lines decide the ports: SIP trunks over the internet or a data link, FXO for analogue lines, E1 for digital lines, and 3G/4G modules on some models.
- Analogue devices you keep (fax, lift and gate phones) need FXS ports or an analogue adapter.
- IP phones are usually powered over Ethernet (PoE), so the switch power budget must be checked.
- VoIP equipment and IP phones fall under SASO’s Technical Regulation for Telecommunications and Information Technology Equipment.
In this article
- What is an IP PBX, and how does it differ from a traditional or cloud PBX?
- How many lines and concurrent calls do you need?
- Outside lines: SIP trunk, analogue or E1?
- IP phones: which type for which location?
- Call management features: auto attendant, queues and recording
- What does an IP PBX need from the network?
- What should an IP PBX quotation include?
- Do PBX equipment and IP phones need conformity certification in Saudi Arabia?
- Common IP PBX installation mistakes
- IP PBX systems from AZEIDK in Saudi Arabia
- Frequently asked questions
- Conclusion
What is an IP PBX, and how does it differ from a traditional or cloud PBX?
A PBX is the core of an organisation’s phone system. It gives each user an internal extension, routes incoming calls and connects the site to outside lines. The types differ in where the PBX runs and how voice travels:
| Item | Traditional PBX (analogue / digital) | On-premises IP PBX | Cloud PBX |
|---|---|---|---|
| Where it runs | Unit on site | Appliance or server on site | Provider’s servers |
| Phone connection | Dedicated phone cabling per extension | Data network (structured cabling and switches) | Internet and data network |
| Outside lines | Analogue or digital | SIP trunks, plus analogue or E1 ports depending on the model | Usually SIP from the provider |
| Existing analogue devices | Connect directly | Via FXS ports or an analogue adapter | Via an analogue adapter on site |
| Expansion | Add cards and ports | Licences or expansion boards up to the model’s maximum | Add subscriptions |
| Internet dependence | None | Internal calls run on the local network | All calls depend on it |
An on-premises IP PBX suits sites that keep landlines or analogue devices, or want recordings to stay in the building. A cloud PBX suits distributed teams with no on-site equipment.
How many lines and concurrent calls do you need?
The most common sizing mistake is confusing users with concurrent calls. A user is any extension registered on the PBX: a desk phone, a mobile app or a DECT handset. Concurrent calls are the maximum number of calls, internal or external, the PBX can carry at the same moment.
The two figures differ within the same model. On AZEIDK’s product pages, based on Yeastar’s official data, the P520 supports 20 users and 10 concurrent calls, the P550 50 users and 25 concurrent calls, and the P570 300 users (expandable to 500) and 60 concurrent calls (expandable to 120).
Steps to estimate the capacity you need
- Count current extensions: offices, reception, meeting rooms, wireless handsets and staff who will use the mobile app.
- Add expected growth over the system’s life.
- Estimate peak concurrent calls from call logs or current line bills, or by observing reception and customer service at peak hour.
- Decide how many outside channels must work at once; this sets the SIP trunk size or the number of analogue lines.
- Add a margin above the peak, then choose a model whose base or expandable capacity covers the result.
Hypothetical example: a clinic with 18 extensions and a peak of 6 concurrent calls fits a small model such as the P520, provided its ports cover the clinic’s lines. If 40 extensions are expected within two years, a larger model makes sense from day one. For a model-by-model comparison across brands, see IP PBX and IP phone brands in Saudi Arabia.
Outside lines: SIP trunk, analogue or E1?
Outside lines connect the PBX to the public phone network, and each type uses a different port:
- SIP trunk: voice channels delivered over the internet or a data link by a telecom provider, with no phone ports needed on the PBX. The channel count is set in the provider contract, and a stable connection is essential.
- Analogue lines: connect to FXO ports. The P520 takes up to 4 FXO/BRI ports and the P550 up to 8; the Grandstream UCM6300 series ranges from one FXO port on the UCM6301 to 8 on the UCM6308.
- E1 digital lines: need an E1/T1 port. The P520 and P550 have none; the P570 takes up to two.
- Mobile SIM (3G/4G): some Yeastar models accept 3G/4G modules: one on the P520 and up to 4 on the P550.
Analogue devices: fax, lifts and gates
Not everything is replaced when you move to IP. Fax machines, lift phones, gate phones and legacy analogue handsets need FXS ports on the PBX or an analogue adapter. The Grandstream HT802 v2, for example, offers two FXS ports and two SIP profiles and supports T.38 fax. List these devices before choosing a model.
IP phones: which type for which location?
Choose the PBX first, then compatible phones, matched to each role:
| Location | Suitable phone | What to check on the datasheet |
|---|---|---|
| Staff desks | Entry-level IP desk phone | SIP accounts, PoE, second network port for the PC |
| Management and reception | Larger screen, more line keys | Line keys and expansion module support |
| Meeting rooms | Video or conference phone | Camera, apps and power draw |
| Warehouses and open areas | DECT wireless handsets | Handsets per base, concurrent calls per base, dust and splash resistance |
| Hotel and patient rooms | Room phones | Programmable service keys, ease of use |
Most IP phones draw power from the switch over the network cable (PoE), and video phones draw more than basic models. Add up each phone’s consumption from its datasheet and compare it with the switch’s PoE budget, using the same method as in PoE switch power budgeting.
Call management features: auto attendant, queues and recording
Features are what set a business IP PBX apart from separate phone lines. Grandstream’s official UCM6300 datasheet, for example, lists IVR (auto attendant), call queues, ring groups, voicemail, call recording, call history, call park and transfer, music on hold and paging/intercom, with conference rooms ranging from 4 on the UCM6301 to 25 on the UCM6308.
Specify what you actually need:
- IVR: a voice menu that routes callers to the right department. Prepare the prompts in Arabic and English and the routing for each option.
- Call queues: for customer service and bookings, with agents per queue and the distribution method.
- Call recording: which extensions are recorded, retention period and storage. The Yeastar P550, for example, uses a USB slot for voicemail, logs and recordings, while the P570 offers both USB and SD slots.
- Remote working: mobile or desktop apps for staff away from the office. Grandstream offers UCM RemoteConnect for secure remote access to the UCM6300.
- Integrations: the UCM6300 datasheet mentions an API for CRM and hotel PMS integration.
The PBXs and IP phones AZEIDK supplies, with each model’s specifications taken from the manufacturer’s official datasheet, are listed under IP telephone systems.
What does an IP PBX need from the network?
Voice quality depends on the network as much as on the PBX. Check before installation:
- Cabling: a data point per desk phone, or a phone that passes the network through to the PC. For cable categories and testing, see structured cabling and network systems.
- Switches: enough PoE ports, with voice separated on its own VLAN and prioritised (QoS) on managed switches.
- Backup power: a UPS for the PBX and the PoE switches, because when the switch goes down the phones go with it.
- Internet: enough stable bandwidth for SIP trunks and remote apps.
- Security: never expose the PBX to the internet unprotected, and enable available encryption. The UCM6300 datasheet lists SRTP, TLS, HTTPS, SSH and 802.1X.
If the building network is still being installed, plan phone points from the start and see our guide to network installation for offices in Saudi Arabia.
What should an IP PBX quotation include?
To compare offers on the same basis, ask each one to state:
- PBX model, base and maximum users and concurrent calls, and what expansion needs (licence, board or DSP module).
- Outside line type and port count (FXO, FXS, E1, 3G/4G) against your existing lines.
- Number and model of each phone type, with a datasheet for each.
- Features included and those needing extra licences, such as apps, recording or integrations.
- Programming scope: numbering plan, IVR, queues, ring groups and user training.
- Network items (switches, PoE budget, UPS), or a clear statement that they are excluded.
- Warranty, post-handover support and firmware updates.
Cost is driven by capacity, ports, phone types, licences and programming scope, not by the brand name alone.
Do PBX equipment and IP phones need conformity certification in Saudi Arabia?
SASO’s Technical Regulation for Telecommunications and Information Technology Equipment (first edition, published in the Official Gazette in 2024) applies to telecom and IT equipment generally. Its annexes cover VoIP equipment, IP phones, wired and DECT phones and PBX equipment, as well as switches and routers. It requires a certificate of conformity from a body accepted by SASO and a technical file, and compliance with licensing or registration requirements and the regulatory requirements of the Communications, Space and Technology Commission (CST) before the product is placed on the market.
These obligations fall mainly on the importer and supplier; the owner should ask for evidence of conformity for the supplied models.
Common IP PBX installation mistakes
- Running voice and data on one flat network without separation or priority, so calls break up under load.
- No UPS on the PoE switches, so phones die at the first power cut.
- Not listing fax, lift and gate phones before ordering, then running short of FXS ports.
- Enabling recording without defining retention and storage.
- Leaving the PBX admin interface reachable from the internet with default passwords.
IP PBX systems from AZEIDK in Saudi Arabia
Through its network and communication solutions, AZEIDK provides complete IP telephony: IP PBXs from Yeastar (P-Series), Grandstream (UCM6300 series) and Alcatel-Lucent; IP phones from Fanvil, Avaya, Grandstream and Alcatel-Lucent; DECT from Fanvil, Avaya and Alcatel-Lucent; and analogue adapters. The system is specified from a needs assessment (users, departments and call volume), with supply, installation, connection and operating configuration, and technical support. Specifications on AZEIDK’s product pages are taken from each manufacturer’s official datasheet.
Frequently asked questions
Does an IP PBX work if the internet goes down?
Internal calls between extensions continue over the local network as long as the PBX and switches have power. Outside calls over SIP trunks stop, while any analogue or E1 lines connected to the PBX keep working.
How many concurrent calls does a 20-person office need?
It depends on peak usage, not headcount. Take the highest number of simultaneous calls from your call logs, add a margin, and choose a model that covers it.
Can existing landlines connect to an IP PBX?
Yes, through FXO ports for analogue lines or an E1 port for digital lines where the model has one. Check the port count before buying.
Does fax work with an IP PBX?
Yes, through an FXS port or an analogue adapter. The Grandstream HT802 v2, for example, supports T.38 fax.
What is the best PBX for a small business?
The one that covers your users, concurrent calls and existing lines with room to grow. Model details per brand are in AZEIDK’s PBX brands article.
Conclusion
Choosing an IP PBX starts with the numbers: users, peak concurrent calls, line types and the analogue devices you keep. Then come the phones, the features, and a network and power supply that are ready for voice. A quotation request that pins these down is what makes supplier offers comparable.
Planning a phone system for your office or facility? Send us your extension count, current lines, analogue devices and required features, and we will propose a suitable PBX and phones with the datasheet for each model. Talk to the AZEIDK team
